It sounds like you could use a shot of cortozone for bursitis
Sorry to hear of the pain you've been in. The good news is that most lumps that are associated with Lymphoma are painless, so I'm thinking this most likely is a reaction to an infection (which is the most common cause of swollen lymph nodes). Have you been feeling ill lately? How about any open sores on your body that look infected? Lymph nodes usually swell because they literally fill up with white blood cells to fight infection. This large amount of white blood cells stretches the lymph node capsule and causes pain.
As far as what to do about the pain, I'd recommend taking an anti-inflammatory like Ibuprofen and alternating hot and cold packs. If the pain is unbearable, I'd go back to the ER or a walk-in clinic.