Testicular Pain/ Scrotal Pain

[goodgrief]

I have a son who recently had excruciating pain after spending time with girlfriend, alone. Took him to ER, pain went away with iv pain med and after examination. Two more visits to girlfriend's house, two more painful arrival at homes. There seems to be hard areas, lumps, in the scrotum, that cause a great deal of pain, and take hours to subside. One testicle swells, he can hardly walk. I guess if there were no lumps i would just say it was too much stimulation and call it that. But with the lumps and swelling, I am concerned and cant find any info online about pain/lumps that occur with erection. He is a teenager and for obvious reasons i have not seen the lumps, but he is very vocal in describing them to me. The next day there is no residual pain. Any suggestions? The uro guy we saw in ER said to come back to his office and we would discuss whether or not he needs surgery, thinking testicular torsion is a possibility. Can that come and go? Surgery sounds drastic, but he cant be around his girlfriend without pain.