When a ball is well balled up or tightened up from holding on to say na arm they often look just like that. Young juveniles looks somewhat triangular as well but as long as you are feeding well and it is gaining weight then not a problem. Unlike some other species, ball pythons are not round like worms, they are slightly triangular and a overly round ball python is an overly fat ball python.
Thanks for your response and yeah he definitely has gained weight since I got him petsmart had him on the wrong size food!