I have a visible lump beside the mid lower part of my spine, and ideas as to what it could be? sometimes pain in that section.

Varies: There are a lot of possibilities, consider getting it checked. Most palpable lumps near the spine are quite superficial and can include benign conditions such as a lipoma, epidermis cyst, or bursa. Some patients with scoliosis will have a "rib hump" die to the rotation in their trunk that some people will describe as a mass as well. A simple exam can usually diagnose it. Thank you.