What should i do about my back pains?

See a dr.: Get an official diagnosis on the cause of your back pain, as it could be due to a urinary tract/kidney issue to muscle strain to more serious spinal issues. Once diagnosed, the treatment can be tailored for your condition. Good luck.

Some thoughts...: Absent testis means what? If undescended, there is usually something wrong in that testicle, related to why it did not descend. It may be smaller and only partly functional. It also has a higher chance of becoming cancerous. If an undescended testicle was not found and moved into the scrotum, nor monitored for changes, etc..., it may still be in the abdomen and have a tumor. Doctor can evaluate.