Uterus stretching

Hello ladies I am 15 weeks this is my second baby but it’s been 7 years since I’ve been pregnant I have a hurting feeling from a scale of 1-10 it’s like a 2/3 on my uterus could this be round ligament pain ? Or baby growing ? I don’t remember what it’s like to be pregnant does anyone know what k may be feeling ? I called my doctor waiting on a response. I feel like I have gas in my stomach and like if I have to fart really really bad sorry tmi I know anyone gone through this before ?

Update took a Tylenol it went away ? So strange