All the best, do take it steady until you get your medication sorted, I must admit I'm shocked you weren't sent straight to hospital, as my recent heart attack was just a dull ache as you describe, I was given GTN in the ambulance which relieved the pain, so please don't do ANYTHING strenuous until the cardiac team at hospital have seen you, oh yes and cycling is considered good excercise as part of your recovery.
Anyway sending healing vibes.