It Felt Like I Was Having Heart Issues As I

It felt like I was having heart issues as I have had this dull pain in my left chest and it goes through to my upper back. I went to emergency and to my doctor....heart is fine. I am not sure how I should proceed to find out what is causing this discomfort? Doctor said it was acid reflux, but does that affect my upper back/shoulder area? Thank you for your expert advice in advance!