Lower abdominal pain at 31 weeks

Good morning! Today I am 31 weeks and the past two nights after I get home from work I experience kind of intense pelvic pain. The only way I can get any comfort is laying on my back. When I try to lay on either of my sides it's really painful and I feel like if I align my hips to be straight the pain subsides. I had an appt this past Wednesday and at that time I was only experiencing pressure on my pubic bones sometimes when I would stand up and they said that was just my ligaments stretching. So I kind of want to assume that's what this pain is but not sure. Has anyone else experienced this and do you think it warrants me calling my doctor? Thank you!!