Lay flat on your back. Put the fingertips of the right hand right in the middle of the bottom of the rib cage, just below the sternum. You'll feel a little bone there. Press in with your fingertips and pull down to the pubis. Hold for a good 10 seconds. It may hurt a bit. Repeat four times. Yoy may have to help the right hand with the left to put the necessary amount of pressure in there.
This little maneuver pulls the stomach back through the hernia and closes the hernia up. Once closed it will heal. It must remain closed so whenever you feel that pain do that little pull maneuver. You'll get good at it and be able to do it standing eventually. But if you keep that hernia closed it will indeed heal up.