Pain in testicle& irritation after urine

This problem started before 4 months. Irritation after passing  urine. after some days tescle pain came. Then I consulted a urologist. I took culture test and abdomen scan. He told me the prostate was little inflamated. And I got a lump near testicle and it's freely moving. Scrotum scan also done. And doctor told me nothing. But am sure there's lump. I told to doctor that scan person not checked properly because he completed the scan within 5 seconds. But doctor told it's not a problem.he gave Some tablet's. I was in complete rest for 45 days. Then it settled down .i came to normal. Then came to work. When I started walking I got the irritation and testicle pain again. Day by day the irritation is going worse. What should I do know? Whether I should go for a scan ? Why that lump is not visible in scan ? Am afraid . Please give me a suggestion