If you’re a beginner, you should train with three full-body workouts per week. In each one, do a compound pushing movement (like a bench press), a compound pulling movement (like a chinup), and a compound lower-body exercise (squat, trap-bar deadlift, for example). If you want to add in 1–2 other exercises like loaded carries or kettlebell swings as a finisher, that’s fine, but three exercises is enough to work the whole body.
The motor proteins actin and myosin generate the forces exerted by contracting muscles. Current recommendations suggest that bodybuilders should consume 25–30% of protein per total calorie intake to further their goal of maintaining and improving their body composition.[30] This is a widely debated topic, with many arguing that 1 gram of protein per pound of body weight per day is ideal, some suggesting that less is sufficient, while others recommending 1.5, 2, or more.[31] It is believed that protein needs to be consumed frequently throughout the day, especially during/after a workout, and before sleep.[32] There is also some debate concerning the best type of protein to take. Chicken, turkey, beef, pork, fish, eggs and dairy foods are high in protein, as are some nuts, seeds, beans, and lentils. Casein or whey are often used to supplement the diet with additional protein. Whey protein is the type of protein contained in many popular brands of protein supplements and is preferred by many bodybuilders because of its high Biological Value (BV) and quick absorption rates. Whey protein also has a bigger effect than casein on insulin levels, triggering about double the amount of insulin release.[33] That effect is somewhat overcome by combining casein and whey. Bodybuilders are usually thought to require protein with a higher BV than that of soy, which is additionally avoided due to its claimed estrogenic properties. Still, some nutrition experts believe that soy, flax seeds and many other plants that contain the weak estrogen-like compounds or phytoestrogens, can be used beneficially, as phytoestrogens compete with estrogens for receptor sites in the male body and can block its actions. This can also include some inhibition of pituitary functions while stimulating the P450 system (the system that eliminates hormones, drugs and metabolic waste product from the body) in the liver to more actively process and excrete excess estrogen.[34][35] Cortisol decreases amino acid uptake by muscle, and inhibits protein synthesis.[36]
Your standard lunge does a nice job of making your derriere stronger, but to get glutes that function at their best, you need to start moving sideways, too. You see, when you do a side lunge or skaters, for example, you strengthen muscles in your outer hips. And strong outer hips can help you steer clear knee injuries. Plus, the sideways moves engage glute muscles so they can reap all the benefits of lower-body exercises. Not sure where to start? These exercises will help inspire you to work your glutes at a new angle.
This leaves you frustrated and yes……….with consistently tight hip flexors.  A crucial step is often missed with trying to stretch away tightness or pain. Before anymore blame is placed on the hip flexor muscle, it needs to be properly assessed. Then after an assessment is performed you can determine what the right hip flexor exercise for you to do is.
2. What's your training like? Are you crushing 25 sets for chest like the average juiced out bodybuilder? If so, there's a pretty good chance you might be working above your MRV (maximal recoverable volume) and as such any physiological adaptation which could have taken place is going to be minimal given the cellular environment which occurs in a state of functional overreaching.

"Your glutes are made up of three different muscles, the gluteus maximus, medius, and minimus," says Lefkowith. "They externally rotate your hip, abduct your hip, extend your hip, and even posteriorly tilt your pelvis." Because of this, it is important that you not only work one or two of these muscles, but rather, focus on showing all of them some love. "If you were only to do moves in one plane of motion, say a front lunge or squat, you wouldn't work your glutes to strengthen all of the joint actions they can perform."

Stand lunge-length in front of a bench making sure your knee does not extend past your toes. Hold a dumbbell in each hand and rest the top of your left foot on the bench behind you. Lower your body until your rear knee nearly touches the floor and your front thigh is parallel to the floor. Then push through the heel of your front foot to return to standing, keeping the back foot on the bench. Repeat for required reps then switch legs.

In addition to the HIIT sessions, it’s always a good idea to go for a 30–60-minute walk as many days per week as you can. I recommend getting a minimum of 10,000 steps every day. Use a phone app to track them. If you’re into jogging, swimming, hiking, or some other form of long-duration, fairly low-intensity cardio, that is fine to do as well, and as often as you like.
Note that this recommendation is for total weekly volume, which means it would need to be divided up based on how many times you’re training each muscle group per week. So, for example, someone training everything twice per week would do 30-70 reps for each bigger muscle group in each of those workouts, and 15-35 reps for each smaller muscle group in each of those workouts.