What Causes Recurrent UTIs And Bladder Discomfort?

Hi, my bladder has an uncomfortable feeling after I urinate. The feeling only goes away if I sit in a hot bath or put a heating pad on my lower stomach. It has been like this for years now and is only getting worse. Originally I got diagnosed with reoccurent urinary track infections, but the last time I went I didnt have a urinary tract infection, but the feeling of discomfort is still there. It is not an STD or anything like that. I am also constipated all of the time and the right side of my stomach swells and has severe pain close to my period. I also have an over reactive immune system. Do you know what this could be? It keeps getting worse and I dont have the money to keep getting random tests ran.