What causes sideaches?

Your muscles are releasing lactic acid and you’re getting cramps. This is known as a ‘side stitch’ which happens most commonly in beginners to exercise.

Drink more water.

suggestions from wikipedia on how to prevent this: Improve fitness Strengthen the diaphragm by using exercises such as those that aid respiratory rehabilitation Strengthen core muscles (abdominals, lower back, obliques) Limit consumption of food and drink two to three hours before exercising (in particular, drinks of high carbohydrate content and osmolarity (reconstituted fruit juices)) Drink water beforehand to prevent muscle cramps Warm up properly Gradually increase exercise intensity when running Exhale when the left foot hits the ground, and inhale when the right foot hits the ground Run on soft surfaces

suggestions from wikipedia on how to cure it while it’s happening: While running, exhale when your foot strikes on the opposite side that the side stitch is located. For example, a side stitch on the right, exhale hard when your left foot strikes the ground. Reduce the frequency of breathing (e.g. in jogging, inhale for four steps and exhale for three steps) Lie down on the back and lift the knee on the side with the stitch up to the chest. Do not breathe too hard, shallow breathing for a few minutes at the same time maintain oxygen input levels. Relax the mind and do not focus on the stitch itself. Put pressure on the affected area, not enough to hurt, but just enough so the pain subsides. Stretch the chest wall and back, whilst laying on your stomach and arching your back,