Good answer, as a retired Chiropractor in Australia, who surfs ( important part that)!
Getting functional spine both cervical and and low back.
I found getting adjusted to get the full spine in its optimal position ( which may not be anatomically perfect ) but optimal for the patient and their history.
Then I suggest a course in Pilates or supportive yoga. Both of which require teachers that can work with the needs of their client.
This builds up the core muscles around the spine and can relieve the pressure around degeneration. For pleasure and benefit also have massage with a good experienced masseur .
Poor posture adds structural pressure causing inflammation which in turn puts further pressure
on nerves emerging from the spine giving pain and dysfunction.
Diagnosis is very important to define the correct treatment and potential for recovery and stabilisation.
Learning correct or modified paddling techniques and pop up techniques can help too.
Moderation in duration and intensity of sessions is important.
I did a free review of the Paddle Air Inflatable Rash vest some years back, they have modified it since then and correct usage of this can reduce cervical strain coming from paddling and the rib pain where the bottom ribs rub on the board.
Summing up if you have back problems surfing seek a chiropractic or medical review. Please ensure that they are at least sports treatment qualified and at best surfers so they understand the postural challenges.
This statement is most important.
If you choose to have the surfing lifestyle realise you are asking an amazing amount from your body , in torquing it moving it and all the things you do.
Maintain it for these purposes, by having your health back up team, design you a set of good exercises and bloody well do them
My best patients were the ones who outside of a maintenance treatment regularly did all the things I suggested.
The rest were like rally cars driven pedal to the metal and then requiring a complete rebuild and panel beating just to keep moving

I've taken up troll hunting just for fun, instead of a rifle I'll just use a pun! 冲浪爷爷