My chest started hurting, and i felt short of breath, checked my pulse ox and it was down to 77, gradually went back to 88, 94 then 98. my heart rate was racing from 133-140 range. now its a hr 98-100, and i feel generally ok. should i go to er?

You should definitely be examined ASAP in the ER to determine your current cardiopulmonary status in view of the chest pain& dyspnea,?transient significant oxygen desaturation or ?very rapid heart rate & persistence of postevent rapid heart rate. Testing to include resting EKG,cardiac enzyme panel to look for heart muscle injury,D dimer blood test,chest X-Ray and/or lung scan to check for embolism