Since 12/26 I have been experiencing shortness of breath,tingling in fingers alternately between both hands or at same time,pain in middle of back and feeling of nausea but no sweating or chills,back and upper left side pain and like I swallowed a golf ball then it disappears. Went to two trips local ER. Nothing in Ct scan,chest scans or blood, urine tests. Bp was only slightly elevated but otherwise normal. But once there and resting,symptoms dismiss and I go home but this begins again in few hours. What could it mean?