Husband has issue

My husband has had hard painful lumps under his armpits for about a year now . Multiple lumps. I guess they are really bothering him now because I catch him sometimes feeling his armpits but he doesn’t want me to see . I want him to go to the doctor and get checked out but he probably won’t . He claims he went before and they did an ultrasound but they didn’t see anything . I don’t know how true that is because it doesn’t make sense. It’s obviously something but I’m scared he’s afraid to find out