High risk pregnancy and need advice

I'm high risk due to a pre existing heart condition. I've been having pain in my chest that radiates up my neck, into my shoulder, and down my arm. Now, I KNOW it's not a heart attack, and I've been to the ER and to my cardioligist. They give me an EKG, and send me home. I don't know what it is, and it's super hard to function because it's like dibilitating pain. Any idea what would help? Anyone else have this? I've already tried antacids and Tylenol. No dice.