Posterior calf tight. vein inch above achilles bulging and pinching. feels like rubber band around calf several inches above bulge vein. no trauma. ?

Possibilities : Include achilles tendonopathy, partial tear, deep venous thrombosis though would have to be considered. Anytime a dvt. Is a question you need to be examined in person....This is a serious problem if you would have it....See a doctor for correct diagnosis.

Get eval: If painful and problematic, best for you to get an eval. May be phlebitis, muscle sprain, tendon sprain/injury, may be a dvt. Without an exam tough to say, best wishes.