Chest pain 2 weeks. Post-xray/ekg/blood/echo sent home as "anxious." since—3 day fever, sore throat/lymph, chest pain swallowing. Relax or more blood?

Viral infection? Sounds like some kind of viral infection... See you doctor just to be sure...
Probably viral. If all of the tests are negative you probably have a virus if sick and/or anxiety. I would recommend that you wait about 2 weeks and if still sick then re-visit your healthcare provider. If still symptoms and all tests etc neg then maybe a consultation with a therapist.