What will help with my pain from Diastasis Recti? It is 4" wide. I'm a man, 68 yrs I have had this condition.

Pain may not be from diastasis recti, as it would be rare for a 4" diastasis and in a male. However, hernias can occur within a diastasis recti. Have you been evaluated for a hernia, which can be causing the pain? Especially from a cough, getting up, and lifting. 

A diastasis is a separation between your rectus abdominus muscles, that you describe as 4 inches.  This separation is not a hernia, or a hole, but a stretching between the muscles, causing a bulging effect.  Your pain may be related to this stretching feeling.  You will need to have the muscles repaired and brought back together.  This can be done with or without a tummy tuck type of maneuver to remove any loose skin.  Once your abdominal wall has been repaired and healed, you will likely find improvement in your discomfort.
Best Wishes.