They can be both mobile and fixed. They are not often painful, but can be. They are hard. There doesn’t that clear everything up for you? Just kidding. It isn’t possible to know on your own. You need to be evaluated by your doctor who will probably order a mammogram or an ultrasound or both to get at look. Most lumps are not cancer and not likely in someone under 40 years old. Source(s): I am a cancer registrar. 2 years ago 3 people rated this as good Thank You