Depends on the cause of the pain, but if the pain is from overexertion from intense physical activity, may be due to the muscles involved in respiration. The intercostal muscles between the ribs, and...
In small amounts, no.Freon is not toxic. But, it displaces oxygen.So, if you have a high enough concentration of freon in the air you breathe, you actually asphyxiate (lack of oxygen to the brain)...