Explain the condition called painful joints (arthritis).?

Involves soft tissue: Arthritis in joints starts as an inflammatory reaction in the soft tissues (synovium) lining the joints. It subsequently when chronic or severe leads to weakening of the ligamentous support and altered fluids within the joint which damage the frictionless cartilage surfaces.

Arthritis: Arthritis. There are 200 varieties. Rheumatologist evaluation needed.