What sport should you start doing if you have problems with the spine?

Tai Chi and Qigong.

With them, your body will learn to maintain posture and movement, safe for the back. The muscles of the legs and kurpus will be strengthened. Will give the skill of vertical movement in an air environment that is safe for your back.

Swimming.

Will give a load for the muscular and cardiovascular system.

Nordic walking.

Works more muscles than running, safe for joints and back, unlike running.

As already correctly said, it depends on the problem and also on the affected department. I will briefly try to outline protrusions and intervertebral hernias in the lumbar spine (as the most frequent)

Provided that the treatment has been completed and there are no exacerbations, it is necessary to play sports, excluding twisting movements and limiting (not forever) the axial load on the spine (from top to bottom )

Twisting movements loose the discs between the vertebrae and aggravate the problem - the corresponding martial arts, freestyle swimming disappear. The axial load will cause exacerbations, so you should not grab the barbell outright. Running is healthy, but again in moderation (just jogging or playing sports). Also, just physical education on horizontal bars-uneven bars will not hurt.

You should not immediately run to stretch the spine without first strengthening the muscle stabilizers. Strengthening should start with static loads (planks), smoothly moving to dynamics (boats, hyperextessia), very slowly increasing the load.

If you don't want to be just a physical cultured, but want to "return to big sport", I advise you to find a good specialist on rehabilitation (unfortunately there are very few of them in the cis)

It depends on what kind of problems with the spine, because this concept implies not only scoliosis, but also many other diseases. Not least is your age. The best advice in this case is to see a specialist. The orthopedic surgeon will prescribe gymnastics that suits you and, if necessary, refer you to exercise therapy, massage or electrophoresis, or prescribe wearing a corset until your back muscles "learn" to maintain the spine in the correct position.

Swimming. It develops the whole body, the muscles of the back are no exception, therefore it will become easier with the back. I do not know what your exact problem is, but personally, with scoliosis after six months of training, the bends were almost not noticeable and the pain went away.

But it is better to consult a specialist, because I am not.