I have a lump on my right rib cage. it's small moves with the skin and not painful. is this just a cyst?

Lump Under Skin: Lipomas, fatty lumps under the skin enlarged lymph glands, usually in the armpits, neck, and groin cyst, a closed sac in or under the skin that is lined with skin tissue and contains fluid or semisolid material boils, painful, red bumps usually involving a hair follicle see your doctor for the exact diagnosis.

Skin lump: Usually possibilities include a cyst, a lymph node, or a lipoma. However there are many other rarer possibilities. It is prudent to ask your doctor to evaluate the lesion. You should go promptly if the lesion is growing or changing.