When I don't have sex I don't feel any pain, but as soon as I have I end up getting a tear at the opening of the vagina and its always on the right side afterwards it becomes very painful

Is this after you have sex?

Yes does it mean my vagina tissue is too sensitive

Well, you need to see the doctor about this one. What is the size of the penis? Too big? Is it rough sex? Do you use a lube?