Thanks for your question on Health Care Magic.
I can understand your concern.
No, these symptoms are not suggestive of heart problem or connected with problem in Stents.
Pain in collar bone is more likely due to
musculoskeletal pain.
GERD is mostly due to
stress or drug related
gastritis or food related gastritis.
So ask her to avoid stress and tension.
Give her light food, avoid hot and spicy food.
Give her
proton pump inhibitors and prokinetic drugs for GERD.
Apply warm water pad on affected areas for
collar bone pain. She can take painkiller if pain is more.
Don't worry, she will be alright.
Hope I have solved your query. I will be happy to help you further. Wishing good health to your mother. Thanks.