Whenever i masturbate or have sex, around where my uterus is it feels like it's blown up. constantly it feels hard and not normal. what's wrong?

Uterus is muscle: The uterus has a big muscle layer which can contract and firm up. However, a normal uterus is about the size of a fist so it should be pretty difficult to feel yourself from the abdomen. If you can feel your uterus from your abdomen, it may be enlarged due to fibroids and should be evaluated. Fibroids are typically benign muscle growths that can feel hard.