I have difficulty in passing urine without catheter even after cystolitholapaxy. Why?

Hi doctor,

On the thirtieth two months ago, I had a bladder stone removed by cystolitholapaxy. No catheter was put in, and that afternoon I could not urinate. I went back to the urologist, and a catheter was put in. On Monday, it was taken out, and after a few hours, I discovered I could not urinate. The catheter was put back in, and I was put on Flomax. The next day, the catheter was taken out, and again I discovered that I could not urinate. The following day, a catheter was put in, and I was put on steroids (a Medrol pack). Two days later, the catheter was taken out, and I was fine. I could urinate easily. For about a month, it was fine, though with burning after peeing. On the eighth of this month, I began to have difficulty peeing and saw my urologist. On the tenth, I could not pee at all, and a catheter was put in. I was put back on another dose of steroids and also Flomax. For several days, everything was perfect. I could pee easily and without pain. But then it became increasingly difficult to urinate. I was told to double the Flomax dose. On Sunday morning, I could not urinate at all and went to the emergency room. While waiting for a catheter, I was able to urinate. I was put back on another dose of steroids. I am still taking Flomax. I can urinate now, but with pain and with less than a usual urine stream. What is the problem? Kindly give your opinion.