Hubby has two painless lumps one on back other on shoulder.shoulder lump when pressed had foul smell pus in it.back lump is large in size.what it is?

Sebaceous cysts: The shoulder lump is a sebaceous cyst. The back lump is probably a lipoma. See a physician to be sure.

Sebaceous cyst: These are most commonly plugged glands which continue to secrete sebum (oil) which collects under the skin. They are usually harmless, but occasionally get infected or cause pressure symptoms and are usually recommended to be removed (often covered by insurance).