Obnoxious Mysterious Pain

Ok. Through this whole pregnancy (I'm 16 weeks) I've had a lot of pain and pressure in my crotch (TMI I'm sure but it gets better). The only legitimate way I can think to describe it so that someone else can imagine it is I was railed with a corncob (not a normal one, the dried up ones you give to squirrels). Its been like this for two months now. We thought it might have been a UTI but I had a nurse at work multi stick my urine last night to test it... it was negative. This is my second child & I do remember bits of labor for the first, & now we've added to the corn cob an uncontrollable urge to push (which i remember havingnduring labor for #1) ... and nothing happens. Idk what is wrong with me!? Has anyone else had these kind of issues? Or have ideas?