Severe side pains? It's under my ribs, and it feels like I'm being stabbed every time I move what's wrong with me? And how can I make it better?

It . It sounds like you are dealing with cramps. Cramps can be a result of dehydration, vitamin deficiency, electrolyte disturbance (low calcium, potassium, or magnesium), and/or Lactic Acid build up after an intense work out etc. Make sure you are well hydrated, eat a balanced diet, and take a daily multi-vitamin. If the severe side pains persist then you should see your doctor right away. Best of luck.