Howard Stern 'Wack Packer' Hospitalized ... Signs of Heart Attack

2 P.M. PST -- We're told Eric will be discharged from the hospital within the next couple of hours ... docs say it was a case of too much stress being put on his body after the workout and therapy. 

Howard Stern "Wack Pack" member High Pitch Erik is in a NYC hospital after suffering symptoms of a possible heart attack.

Joey Boots, Erik's friend and fellow 'Stern Show' veteran, tells TMZ ... Erik worked out with a trainer Thursday morning and later saw his physical therapist. During his session, Erik began to experience numbness in his legs, tightness in his chest and tingling in his left arm.

We're told Erik's therapist immediately called an ambulance and he was taken to a local hospital.

Erik's currently undergoing tests but is stable.