Hi I am Thejeswar. I am a Medical and hematooncologist. First, get a clinical examination by a doctor. Non-mobile mass means fixed mass to underlying structures. In that case, you can have pain and mass size also will be more. However, I will mention some features of benign lumps 1. Presence of a palpable lump: You may feel a distinct lump or mass in the breast or armpit area. The lump is usually painless and movable. 2. Smooth texture: Benign lumps often have a smooth, well-defined texture and can feel round or oval-shaped. 3. Changes in size: Some benign lumps may fluctuate in size over the course of your menstrual cycle. They may become more prominent or tender before your period and then decrease in size afterward. 4. Multiple lumps or cysts: Benign breast conditions can sometimes result in the development of multiple lumps or cysts within the breast tissue. 5. Absence of other symptoms: Unlike cancerous lumps, benign breast lumps typically do not cause nipple changes, skin dimpling, nipple discharge (other than milk during breastfeeding), or significant breast pain. Remember that these symptoms are general indicators and not definitive proof of a benign condition. It's important to consult with a healthcare professional