I have what feels like a lump between my thumb and index finger and there is pain between my index and middle finger what could it be?

Common hand lumps: Include ganglion ( cyst) , foreign body, or it's inclusion cyst or epidermal inclusion cyst, benign solid tumors . Nodules from dupuytrens disease, gout or inflammatory arthritis. Malignant or metastatic disease can occur but is very rare. At times tendinitis is associated with swollen tissue that feels like a lump and nerves or blood vessels can swell talk to your pcp and/ or see a hand surgeon.