After doing weights noticed for a few secs there is no pulse in left wrist or faint, gp said left blood vessel probs narrower, pulse everywh else stil?

Doctor can evaluate: Such symptoms may be due to increased muscle size from weight training. The increased muscle size sometimes compresses the blood vessels (don't want that!). Nerves may get compressed too. A sports medicine doctor can evaluate. A vascular or thoracic surgeon can give an opinion too (who can treat problems like thoracic outlet syndrome). Meanwhile, one may consider stopping training that muscle.