Secreting a colorless fluid in penis all time..help?

3 weeks ago i have a problem with urinating...it comes out with two much pressure..then after one week when i tried to masturbate i secret blood and a yellow thick fluid...after that all the urinating problem solved.but i went to consult a doctor,and he gave me 2 tests. urine culture & kidney x ray..after the tests results are normal. but after 1 week i am always secreting a colorless fluid in the tip of my penis. always secret 90% of the time. i am worried. is it a major decease. i have not done any sexual relationship with anyone.please suggest me