Recurring periodic lump in left armpit.

Hi doctors, I facing sudden marble size lump issue in mine left armpit since 7 month. It comes with size of small pea and goes till. Marbke size. It increases size in few min (in 30 min) it starts with itching and then gets normal. It feels hard on touch. It stays for few hours like 5-6 hour and then gets normal and again comes after 4-5 days. I do not have other symptoms like fever, night sweats or wright loss. I did mine cbc esr and crp.  This swelling mostly ( 90% comes in night)  and goes away in morning. I did axilla ULTRASOUND of that area twice and all came NORMAL. First ULTRASOUND did not mention size of lymp node but 2nd ultrasound mentioned size like 20mm*4.4mm left side and 11mm*3.1mm left side. Preserved fatty hellium. radiologist said it is normal size. All came normal.  It has  reappeared once since last 4 week and went off in 2 hour. I am really concerned if this is lymphoma cancer? Please guide. My age 30, male.