EXCLUSIVE

Just three days before Paul Bearer died, he complained he was suffering a blood clot ... TMZ has learned.

"Cowboy" Bob Kelly -- one of the board members of a prominent wrestling society called the Cauliflower Alley Club -- tells TMZ he last saw Paul on March 2nd at a Club reunion.

Bob says Paul was in bad health, with a severe breathing problem. According to people at the event, Bearer was coughing and had trouble standing for long periods of time. He told people he was going to seek treatment for what he called "respiratory issues."

Bob says Paul went to the hospital immediately following the reunion.

Bob says he was later informed the famed wrestling manager was being treated for a blood clot.