I always feel a frequent need to urinate, feel as if my bladder cannot store that much urine as before. I don't always hold back urine. I'm just always sitting.

Prostatitis can cause such infection as well. When the prtostate galnd is inflamed and enlarged, it oppresses the bladder. Sitting for long can cause poor blood circulation at your perineum area and then cause prostatitis.
You need to visit local doctor and find your specific condition. Common bladder infection can be cured by antibiotics in a short while, please don't worry.                                    
Released in 2011-10-20 15:36:38