Hello, I have studied your case. For nodule you may need PET scan to confirm any metastasis or activity. Nodule may not lead to back pain. According to your symptoms this looks as acute lumbar muscle sprain in your lower back. Most probably due to bad posture or sudden jerk. When such patient comes to our hospital we usually do x ray to rule out any nerve compression. MRI spine will show any disc bulge is there or not. And when muscle sprain is confirmed muscle relaxant, analgesic and neurotropic medication can be started. Till time, avoid lifting weights, Sit with support to back. You can consult physiotherapist for help. Hope this answers your query. If you have additional questions or follow up queries then please do not hesitate in writing to us. I will be happy to answer your queries. If you find this answer helpful do not hesitate to rate this answer at end of discussion. Wishing you good health. Take care.