I had a head injury over 2 years ago (age 30) from running head to head with someone while we were both running at top speed. I had a year and a half of constant dizzyness, accompanied by a lot of fatigue, headaches, frequent migraines (2-3/week), blurred vision, plugging ear, photophobia, phonophobia, head pressure, and insomnia. I did not notice any cognitive or memory problems, except the distraction that the other symptoms would cause. I was helped a lot by a chiropractor who was an upper cervical specialist. But alas, the adjustments would fall out with the slightest things, like a hard sneeze, or tripping a little on the stairs. So, I asked him for exercises, and he recommended aquatics as a good way to strengthen the neck and upper body. I could not do anything that involved impact, so the swimming made sense.
So, this summer I went to the lake a lot, and swam for several hours at a time. The effect was really noticeable and immediate. A lot of times, I could go to the lake feeling full of head pressure, dizzy, and other symptoms, but come home feeling like a new man, full of energy, and no head pressure. Also, I had a lot less problems with insomnia at night. I have wondered if it is due to the following:

Cold Water - The lakes here in WI never get very warm (70s), and maybe the cold reduced swelling or something?

Exercised Muscles - Maybe the shoulder muscles being exercised helped the inner muscles of the neck next to the brain stem to relax?

Areobic - Maybe the areobic exercise got more oxygen to the brain? I have read that the brain consumes almost 1/3 of your body's oxygen supply.

Over the past few months, I have made a huge amount of progress, and even was fairly symptom free for 4 days in a row! I also have not been to the chiropractor for about 5 months now. I even had a few mishaps, but it never seemed to pull the upper vertebrae out of place anymore, because the muscles were stronger. I have still have ups and downs, but overall I have been doing a lot better. Some time ago, I was away from home for a while and unable to swim. I started having more noticeable symptoms again. Has anyone else out there found swimming to be a help with PCS?

I have also been taking magnesium, and trying to take it a little easier in general (as a father of two (soon three) and running my own farm, and doing church work too, it can be challenging).