What to do if i have aches in upper and outside thigh, don't know where from so should i use icy rubs or my electric 10's unit ?

Heat: I might actually recommend first trying an antiinflammatory like ibuprofen 600 or 800mg every 6 hours or naproxen 500mg every 12 hours and then also doing heat like with a heating pad first. If those don't work, then try the Icy Hot patches or gels or whatever preparation you have. I'd see your doc before starting with the tens unit so they can do a more thorough history and physical first.

Pain: It is probably muscular. I would try an anti inflammatory rub and iIf that does not help your Tens unit may.

Thigh aches: This discomfort may be from strain/inflammation of the thigh muscles or referred from pressure on a nerve or nerve root in the spine. If it's muscular or from injury,cold applications for 24-48 hours and then swittch to heat may help. Nsaids like ibuprofen and tens unit help relieve nerve pain. If symptoms persist,see your physician for diagnosis and treatment.

Either: If you think you had an injury to your muscles ice is very reliable. If you have a chronic type of pain the Tens Unit helps especially for the back. If you have arthritic joint discomfort consider heat. Hope you feel better soon. If it does not resolve give your doctor a call so she can analuze this with you.