Your butt is one of the most powerful muscles in your body, and if they are weak, it can cause many problems and especially bad posture.
Please try this routine because this is some of the most powerful exercises that helped me get rid of my hip pain/back pain and some other pain I had connecting with my weak glutes.
For best results do this routine twice a day
10 reps of the Glute Bridge with exercise band x 2 sets
Exercise bands i use
Plank hold 30 seconds x 2 sets
Best of luck to you!