I am a 22-year-old male, and I have a frequent intense urge to urinate. Please help

Hi doctor,

I am a 22-year-old male, and my height is 74 inches, and I weigh 225 pounds. Currently, I am taking tablet Oxybutynin 5 mg once a day. I have been dealing with issues of frequent urination for the past seven months. The doctor told me to try behavioral changes (more bowel movements, no caffeine, more water). Still, it did not help at all, as well as taken blood and urine samples and ultrasounds on my kidneys and bladder found no apparent cause. The issue is a frequent intense urge to urinate, even after going to the bathroom. The tablet Oxybutynin helps me empty my bladder, but it does not help the constant urge to go away, and unfortunately, my doctor has not taken any other actions to try to find and treat the root cause. Some days it is better, and some days it is worse and has been noticeably exacerbated by things like my job when I am in court on jury duty. I cannot tell overall if things like stress or anxiety worsen it, but I definitely cannot rule it out. Any advice or possible ideas of what the underlying causes or treatment could be is greatly appreciated. Also, I experience no pain or tenderness, and the ultrasound showed no issues in the bladder or kidneys. Doctor found no problems with blood and urine, no nitrates or blood to indicate a UTI, and tablet Flomax and tablet Oxybutynin has not solved the problem. I do not have the insurance or money to keep seeing the urologist, so I hope to find some help here. Thank you.