Heaches 'after excercise' can be a sign of IRON DEFICIENCY. But do not take supplements until you know for sure by gettig a blood test.
Iron is a heavy metal , and it does not leave tissue easily. It can build up quickly and cause poisoning and even death. So, get a blood test.
Because iron is so hard to release, there is usually a malfunction somewhere in the body when low iron is present. Bleeding ulcer, excessive menstruation,or stomach parasites like the bacteria H pylori. In fact bacteria needs the host's iron to surive and replicate.
The other possibility is a magnesium deficiency. general heaches and migraines are classic signs. Magnesium malate, 500 mg a day, or magnesium citrate would be a prudent thing to try. Most people are very low on MG because our common diet does not include the richest sources.