I had/have chest pains for years and years, I associate it with Lyme/Bart. I had EBV, but it I didn't get that symptom then.
When it's too bad, I go and see my ostheopath, he loosens all the tension that has build up in my chest. It (really) hurts the first 2 days after treatment, but then it gets really better. It's a scary symptom, but try not to worry too much about it.
I know all about the sudden switchen in energy. Some days start with not too much pain, but it can change from one minute to another and turn into a horrible day. Just go day by day, hour by hour.