What Causes Dull Ache In My Upper Leg?

Hi, my upper leg/butt muscle has been in pain for the last 4 days. The pain is occuring in my right leg only and putting on clothes has been troubling. The pain is most severe in the morning and evening. It has been tough to walk at times because I feel like I have to limp. I am looking for what I should seek. I've tried Icy hot patches and massages.