Hi,Dear Thanks for the query to HCM virtual Clinic. I studied your query with available details given in your query. I understood your health concerns. Cause of the painless testicle lump with back pain- Your query has swelling in testicle with pain in back and scrotum. This swelling has come down with a painless lump in the testicle. This story is bit confusing in your query and hence needs a Second opinion from ER Surgeon,as its very necessary to confirm the possibilities which arise from the query facts-as -this lump could be due to -a testicle swelling which has pain in back-indicating spread of the swelling to the lymphnodes in the abdomen. This lump lately has grown down -indicating a secondary hydrocele,which pushes it down by the increased weight, which got developed in to the swollen testicle-Such a lump could be Seminoma with spread in abdomen or in the mediastinum with low back pain with secondary hydrocele. -Or it could be due to the Spermatocele with pain in back due to the neural supply from abdomen,which later had Seminoma developed in such a testicle. So consult a ER Surgeon who would differentiate it by duplex imaging USG study after Clinical examinations.. My clinical opinion on your query is- PET CT Scan with mediastinal/para-aortic node biopsies would confirm the duplex imaging USG studies of such a lump in your case. If not, Surgical Excision Biopsy with HPR would confirm its cause as benign or malignant testicle tumors. Don t Self-treat or medicate in your case as the case may go in to further complications. Hope this reply would resolve your query and would help you to plan treatment with your doctor. Hope this would relieve of your health concerns. Welcome for any further query in this regard before final suggestions are given in your query. Wishing you fast recovery.. Have a good day. Dr.Savaskar M.N. Senior Surgical Specialist.