I believe it's fatigue. It happens to me sometimes. It feels like I'm dragging around 50 pound weights on my legs.

The pain in your hip, in my opinion, has to do with your walking gait. I've noticed that my gait has definitely changed and, in an effort to keep my balance, I tend to walk with my feet farther apart than normal. As a result, my hips tend to get more of a work out than usual. Now....if this would result in a loss of inches in that area I wouldn't complain.... but so far it hasn't.

I hope you feel better soon. It stinks when we can't do the things we used to.