Hello I appreciate your concern. Bump in the shaft of penis might be related to hematoma (collection of blood) due to injury during masturbation, pyeronie s disease, fibrous plaque or allergic reaction. Here, I would like further information for better assessment of the condition if possible upload me a photograph Is there any visible angulation in your penis.? In my opinion you should see general surgeon for physical examination and if need be surgical correction of the bump. Hope I could answer your question please feel free to ask for follow up question I will gladly answer you. Best wishes