How Should Umbilicus And Urination Pain With Frequency, Stomach Weakness Be Treated?

I am a 21 year old male .I have been occasional sharp pains on my belly button something that I cannot feel when I am stooping forward,but when I stand up straight it hurts me like madness.It also drives me crazy when during such pain i try to urinate.It seems like a string attaxhed from my navel to lower abdomen and somebody is beating upon that.I had 3 major such attacks in the last three years with mild few of these.This usually subside by itself after a few hours.I have visited a number of docytors including general,medicine,urologist and gastro ,none of them initially could say anything except there is nothing wrong.Then with recurrence of such problems they told me to do tests .I did ultrasonography of the whole abdomen,colonoscopy and a couple of urine test (routine culture and sensitivity)All the tests came negative.Doctors were of the opinion that i have ibs .I always had a weak stomach with gas problems and mild constipation.Things were still ok till the last three months.The last thee to four months i am having some added problems.I am having a feeling of urination almost all the time even after urinating pretty frequently.I have stopped almost stopped masterbation but even then very seldom when i ejaculate i feel pain and uneasiness in my lower abdomen.I am usually pretty stressed and have adepressive tendency .What can be the case am i having some serious sexual issue .PLease help and sorry that the post is so lengthy.