I am experiencing a muscle like pain in my left upper/outer thigh when i tilt my head back, walk barefoot and sometimes when sitting. i don't remember injuring my leg and i'm very active. am i just getting old? i have spent a lot of time outside?

It is difficult to know what that is without examining it but it could be a pulled muscle from all your activity. If so, it should begin to feel better in a few days. If it does not improve in a few days, then have a doctor examine it. You could try either heat or cold, whichever makes it feel better. You could take either acetaminophen or ibuprofen-ibuprofen is anti-inflammatory. Good luck!

Rather than a.muscle symptom, I'd be suspicious of a nerve impingement syndrome emanating from the lumbar verterbrae. A bulging disc or vertebral spur are common causes. A neurologist would be best to evaluate you and order appropriate testing.