Can sciatica make you sore?back of my thigh hurts, didn't do anything to make it sore except stretching, not swollen or red.could it be a clot?not sure

Sciatica is pain: Down back of leg, clot probably not! strain probable --see pcp if it persists.

Sciatica: Pain in the distribution as you suggested describes the pattern of the nerve that travels in the leg called the sciatic nerve. The sciatic nerve is not the cause of the pain source, it is the result of an irritated nerve typically in the lumbar spine (low back) which are caused by herniated disks, spinal stenosis or degenerative disc disease requiring further evaluation by a spine specialist.