My mom is having health problems?

I'm really scared something bad might happen to my mom because of her health. My mom complained of chest pain a couple times this year and a month or so ago she got an ultrasound and they found gall stones. Will this turn into something bad eventually? Also about a few years ago she had to go into surgery because she had a very tiny thing in her but she is fine and it was not cancerous. Also she has trouble breathing sometimes if she bends down. Why could that be happening? she is not overweight or anything she is fit. She also just told my dad that last night she had very strong pain and that she felt she couldn't breathe. I don't know where exactly but she said that if she hadn't woken up at that moment she could have never woken in up in the morning and she might have been dead. This really scares me to the point that I want to cry. What could be wrong with my mom? she also works two jobs in one she works about 9 to sometimes 10 hours about 5 days a week and in a part time at night 5 days a week also till about 9 at night could this also be bad for her. She is only in her very early 40s. I'm really scared. PLEASE HELP ME!!!!!!!!!!!!!!!!!!!!!!!!!!!!!