The average human can sustain a ridiculous amount of injuries over the course of his or her life. Some of these injuries are more serious than others. Some joint or spinal injuries received early in life can cause pain that lasts well into the golden years. Some of these can be alleviated by surgery, but the results are not absolute and the surgeries themselves can be rather expensive.
Is there a source of relief? Can you regain the mobility that you once had? As a dreamer, can you perhaps even SURPASS your previous level of strength and mobility?
Strength training is truly a great way of overcoming the injuries that you sustained. Isometric exercises can offer great relief for those with tendon or joint injuries. Muscle control can offer relief to those with muscle tears and strengthen the immune system. Hand balancing can help to repair shoulder injuries. Partial lifts or support lifts can alleviate lower back pain or a slipped disc. The stomach vacuum can help with an array of digestive issues. Breathing exercises can even help lower blood pressure.
Diet is also a strong component of rebuilding the body. A number of foods that have obvious benefits also offer healing qualities not initially apparent. For instance, avocados are known for their antioxidant density and cholesterol reducing properties. They are not as well known for their seed, which has anti-inflammatory properties, which can aid arthritis. Also, the fresher and less genetically modified the food, the better healing properties it has. Live foods are better than raw foods in this sense.
When you eat food, you not only absorb the nutrients in that food; your body is processing the DNA of that organism. Genetic modification alters the food's DNA for the worse, and those alterations can affect your own health. Also, the more acidic the food you eat, the more detrimental effect it can have on your health, and thus your rehabilitation.
However, certain foods that contain acids (oranges, lemons) are still considered alkaline because they do not contribute to making urine acidic. Googling "dr. sebi", "electric foods", or "alkaline diet" can give you a better scope of this concept. The best summary I can provide is for you to try and eat fresh, dark vegetables (a garden would be optimal, but not everyone has a green thumb) and plenty of fruits or nuts. Avoid foods with unhealthy fats (foods like salmon and avocado will benefit your health greatly), and try to avoid "dead" foods (fried, synthetic, leavened breads, etc.)
People with lingering injuries should not stray away from physical activity related to the injury, as this is a defeatist attitude to consider that the injury would not heal or that all physical activity would worsen it. Pseudo-science and paranormal info to the side, the regenerative properties that your body can achieve with your state of mind alone can be quite astounding. Yet, it would take an approximate miracle to think yourself out of that 12 year old knee injury. In such cases, exercise is the appropriate way to repair yourself. Partial lifts (sub-maximal to maximal weight moved only along the strongest range of the muscle) can make true differences in the speed of your recovery. For more on that, check out Bud Jeffries' program Training With Partials. In addition, isometrics is one of the best rehabilitative forms of training period, so performing them, not too strenuously though, can skyrocket your recovery speed. Learn more about isometrics here.