I had a hysterectomy 3 weeks ago and now I have to urinate frequently with discomfort in my bladder

There could be a link - remember that all the "parts" down there are very close together, so when you take something out it causes other things to shift around a bit. I would mention it to the doctor.

Could be a couple of things. If you had a catheter for a day or so after your surgery, you may have a bladder infection. Surgery in the pelvic area can irritate the bladder and nerves in that region, causing urge and frequency. You can get over-the-counter UTI tests. If it turns positive, check with your doctor. Even if the OTC test is not positive, that does not rule out a bladder infection. Best bet, if it doesn't get better, you are having fever greater than 100.5 or it gets, see your doctor.