Heart Spasm at age 25 - HIGH troponin

My Fiancee is 25 years old, 5'4", and about 105lbs.  About a month ago went into a hospital for UTI symptoms... was given an antibiotic where she had a reaction to it and we went back later that same evening and got a different antibiotic (not in the penicillin family I think - Bactrim?)  It continued after antibiotic course was done, so she was put on Levaquin.  Sometime here she woke up in the middle of the night with back and chest pain (sternum area) and shooting pain / throbbing down her left arm for almost 1 hour.  Hospital showed Troponin levels of 26 which is the highest this hospital had ever seen.  Heart cath was done - no damage visible.  Echo was done - looks fine.  Cholesterol, blood pressure, EKG, ECG... all fine.  The only other test that came back abnormal was an ANA test on her bloodwork.  She was put on Norvasc (calcium blocker) but it only made her heart flutter more.  Now they took her off that and are treating it as if it is some type of acid reflux.  Her chest and back pain continue and is more 'apparent' late evening to early morning.  We are just frustrated that everyone is 'mystified' and can not give us a direction to follow to try to find what the 'trigger' may be that causes this.  What steps can we take to reduce the frequency (almost daily/nightly) of these chest and back pains?  Are there different things to look for in a younger age group than older?  (I find most online articles have been dealing with older categories of people).  Stopped smoking and drinking red bulls over a month ago too.  Cat scan also shows everything is fine.  What are we missing?