What causes pins and stinging feeling in my thighs?

Pinched nerve? Usually that type of feeling is coming from the nerves being pinched or pushed on somehow. The skin neves run along the top of the thigh, so make sure you are not wearing tight pants. Also, leaning against a counter for several hours can cause that. They can also be getting pinched due to arthritis or other problems in the spine. That is more likely at your age. I'd see your doc to get checked.
See below. Problems like these can only be correctly handled by your doctor in person. He/she needs to listen to you, perform an examination and possibly run labs or other tests. That's the only way he/she can find out what's going on and what to do about it.