What Causes Sharp Pain In Pelvic Area?

Hi my name is Ange carter I have been having pains in the pelvic area since Oct. the first time I seen the doctor she said that I had UTI my preiods are not regular and the pain is between a 5 to a 8 all the time even sharp pains come mow and then tryimg to get up from laying down two weeks ago I had an altasound the cervis nd every thing was ok except the thicking of the uturus I am 45 years old