Call your doctor first and describe it to them. It could be where your hips are spreading. You would think by the 3rd one our hips would be done lol, but mine are doing the same thing. See what they say, tell them you done the tylenol and left side thing, that you went to ER and found out you have a UTI and are dehydrated and see what they say. My poor nurse at my docs office doesn't even have to ask my name anymore lol, she knows my voice. Even if you haven't been to the doc yet, call the one you are going to see.
Call ur dr and they will have an on call nurse call u and tell u what to do. Id do that before going to hospjtal. Hopefully nothing serious but better safe then sorry
When I was pregnant with my first son I got a UTI and they sent me home with the proper meds and a couple of weeks I got the same pain you are talking about so I had my husband take me back to the hospital and it turned out it had turned into a kidney stone so if it makes you feel uncomfortable I say it's always best to get checked out