If you have pain on the outside of the thigh, or down in the groin area, you may be experiencing meralgic paresthetica.
Meralgic paresthetica can cause this type of pain on the outside of the thigh to extend down to the knee. You may experience burning, tingling or numbness, or the area may ache. Meralgic paresthetica usually affects one side of the body.
Sometimes clothes that are too tight, or items like a tool belt, can put pressure on a nerve and may create this condition. Being overweight can also lead to meralgic paresthetica.
The obvious strategies would be to stop wearing tight clothes, or your tool belt. If you're carrying unwanted pounds, weight loss is a good idea. If steps like these don't bring improvement, your doctor can advise you as to appropriate treatment.
"Finally, we should mention the possibility that a form of diabetic neuropathy, called proximal neuropathy, can cause the symptoms you have complained of. Your doctor will certainly want to know if you have any diabetic symptoms, and may want you to have a fasting blood sugar level done."
http://www.healthandage.com/Thigh-Pain