advise ?

So I recently got my test results if I had any infections in my vag that could be the reason for my painful sex.. everything was all good and no infections what's so ever! I actually done a re test because I didn't really believe I had nothing.. and everything came out perfect :/ the thing is the head goes in easily and a bit over that but when it wants to go deeper it hurts so bad.. anyone know why? Is it just my vag??