How Can A Lump On The Shoulder Be Treated?

hello, I've been having a somewhat large football shape lump on top of my shoulder near the neck. Can't think of an object that would come close to the size. It's bigger than a golf ball but smaller than a pear. At first, I thought nothing of it since I do carry heavy bags and my purse so I assumed that it's just a knots in my muscle that needed to be kneaded out. But I just got out of my massues appointment and she was worried about that huge lump in my shoulder and ask if I've seen a doctor. I didn't really see the need to see one since as I've said before, just carrying around 20 pound or more bags almost every single day but now I'm not so sure. Should I scheduel an appt with my doctor to get an x-ray of it or should I wait and just recorded the lump for the next month or so and go to the doctor later if it get bigger.