What Causes Arm Pain?

A couple of weeks ago I had a leg pain localized on the back if my right leg, spanning the entire area beneath my butt to the back of my knew. I can only describe the pain as similar to flu like ache. It was excruciating, my skin and muscle ached to the bone and was super sensitive to the touch. I took motrin and rubbed on icy hot on the area. The pain ran its course in a few days. I now have the same pain on the back of my right arm. Although not as intense if a pain the skin seems to be more sensitive to the touch, with clothing brushing against the area making the skin and muscle ache. I have never experienced any symptoms like this before and have no other noticeable symptoms.