Lymph nodes that enlarge due to lymphoma are usually around your neck/collarbone, your armpits, and groin area. However, you have many lymph nodes throughout your body and any of them are susceptible. How long has the lump been there? Is it getting larger? Do you have any other symptoms you are concerned about?
If you're concerned about it, you should error on the side of caution and have it looked at by a doctor.