I agree with Joy! Your body is also making room for your growing baby.. I had a lot of pelvic pressure during my pregnancy. Very common but if it gets unbearable call your doc ASAP. Have a nice warm bath or put a heat wrap on to help with discomfort.
Pelvic floor pressure is a common pregnancy complaint. But, as the other ladies suggested, when in doubt always contact your doctor.
I get that pain you're describing sometimes too, but that never started until after I gave birth to my daughter.
I would cunsult your obgyn about it.
It's hard to say from your description, if it concerns you call your OB. Otherwise my suggestion is that it may be ligament pain.