I think you have carpal tunnel - the guitar playing is a repeatative motion activity. You can have carpal tunnel without pain, or with pain. the cyst like lump may be a build up of fluid that, over time, turns in to jelly consistency making a hard lump. Look it up on internet.
Your association of your hand problem with your breast ca problem is not the first logical conclusion (although to a lay person with breast ca - it is a constant worry that the Cancer is somewhere else hiding). Breast cancer spreads to brain, lung, lymph nodes and bone...it is highly unlikely that your first symptom would be a cyst like pain in the hand/wrist area...its more likely carpal tunnel. Good luck...
Hi.
The large lump in your lower palm area could be a tendon cyst, which should be excised as this would increase in size over time, making hand movements difficult.
It is still best to consult your physician for proper evaluation and management..
Good luck.
I do not know if you know, but there are cancer institutes out there that will treat you whether you have money or not. The Huntsman Cancer Center in Salt Lake City is one such place. They will not turn anyone away because of no insurance or inablility to pay.
It is worth going in to have them evaluate you. You can also get surgery there if needed.
Good Luck! Teri