My penis is curved and when I get a full erection it can be quite sore, I was wondering if this is normal or might it be a problem.
Hmmm, give a more precise description of that curve. It's most likely normal, but on a better safe than sorry policy, try to describe it.
About half of penises are noticeably curved when erect, and it's normally no problem. However, if the curvature makes it sore, that suggests it's worse than normal curvature, and possibly Peyronie's disease, where curvature is caused by scar tissue forming on one side. You'd need to have a urologist check that out. If the curvature isn't severe and it isn't getting any worse no treatment may be warranted.