First suggestion: Do not jump on a trampoline with a sore back.
Second suggestion: Get rid of the soreness in the back first.
Third suggestion: Throw away the trampoline and go row a boat.
Again, get someone to run his or her fingers down the spine to feel if there are any indentations or protrusions. They indicate spinal disc herniation and spinal disc compression.
It would be more fun if this were done in the nude.
Stand with the back against a wall. Raise both arms until the back of the hands touch the wall. Stretch the arms upwards. Relax and bring the arms down. Do this six times. Soreness in the back should lessen with this exercise.
Slowly bend backwards with spinal disc protrusions and slowly bend forwards with spinal disc indentations. This bending exercise should be done very slowly over the back of a dining chair with supervision.