What could be the possible cause of painful lumps under the skin on both shins? there is no redness.

Erythema nodosum?: A condition called erythema nodosum typically causes painful bumps over the shins. Usually there would also be redness, but not always. Erythema nodosum often is a sign of other systemic inflammatory diseases. For example, it often shows up in people with inflammatory bowel disease, i.e. Crohn's disease or ulcerative colitis. See a doctor if the problem continues. Good luck!