These conditions should be treated with increased water intake - not with a commercial treatment, but a very effective one. It will produce deformity of the spine. It will produce crippling deformities of the limbs. Pain medications have their own life-threatening complications. It should be treated with increased water intake until the patient is free of pain and independent of medications.
Medical supervision is prudent.
However increased water intake may be your cure for angina. Migraine Headache may be a sign that water is needed by the brain, and the eyes. A migraine may be prevented by keeping dehydration from establishing in the body, and may be totally cleared up by treating for the condition of dehydration. This particular type of dehydration, might eventually cause inflammation of the back of the eye and possibly loss of eyesight. Colitis Pain is a signal of water shortage in the large gut.