I am on number 5 and each one the pain came sooner and was worse. Definitely mention to your dr...but mine said it's normal. :(
I got pelvic pain WAY earlier the 2nd pregnancy than I did the first, like barely outside the 1st trimester, and it was pretty uncomfortable for a few weeks and let up til the end of my pregnancy, I just delivered a healthy baby girl so it was normal for me. I'd mention it to your doctor though just so he/she knows.