Was told by a doctor after a slight changes in an ECG test following chest pains to call an ambulance if I experienced more chest pain. I did this last week, rushed to hospital but multiple ECGs and blood test all ok (doctor thought it was indigestion). Saw cardiologist two days later and she thought it might a blockage and is arranging a nuclear stress test but told me to ring 999 again if more pains. Pains returned, quite severe the following day so again went to hospital, stayed overnight. ECGs and blood test all ok, different cardiologist thinks it might be costochronitis (but wants me to still do the stress test). Seems unlikely to be an issue with my heart, but do I call an ambulance for a third time if it gets bad again?