Sounds like what they call Honeymoon Cystitis, it's a urinary infection that can be caused by sex, and although you don't have to have just come back from honeymoon to get it that's what they call it. The infection itself is Cystitis, symptoms are frequent urination, and pain or burning when you pass water, plus sometimes a feeling that you have more water to pass but it won't come out.
Honeymoon Cystitis is common in women and girls who have just started having sex or women who have gone back to having sex after a long period of no sex. Lower urinary tract (LUT) symptoms in women are very common after sexual intercourse. Cystitis means inflammation of the bladder and it is usually, but not invariably due to infection. Bacteria are often pushed mechanically up the urethra and into the bladder during coitus. The male urethra, being substantially longer, is not susceptible to the same problem.
The term 'honeymoon' was applied because, in the past, this was expected to be the time of first intercourse. Of course, the condition of post-coital female lower urinary tract infection occurs at many times beyond the traditional 'honeymoon' - from the onset of sexual activity into old age.