I think most people's bodies have some sort of weird thing to them. My elbow used to lock. I would just push it through and it would make a snap. Never hurt though and it went away a few years later.
My point is, if you want a doctor to look at it and find something wrong with it, they will. But if it doesn't hurt and doesn't hinder your movement, it might just be something you live with.
And yes, 45 degrees is OK.