Back of leg is tender?

The back of my left leg (thigh) has been tender to the touch since this morning. I feel it when sitting down or even gently rubbing on it. Is this normal? It doesnt “hurt” necessarily, but it does give off a very uncomfortable feeling and sensation other than being tender.. I tried to see if there were any marks maybe I did something and I noticed like 3 small lines kind of look like stretch marks but not really??? Can this be veins or sciatic ? I’ve read some on google wondering if this happened to anyone else? Currently 17 weeks pregnant