The pain in the chest is often described as pressure, squeezing, or fullness within the chest cavity. In some cases a burning sensation and pain will accompany these side effects. Numbness, pain, prickling or other sensations are commonly felt in the left arm, though these side effects can transfer over to the right.
The formula for calculating the minimum due can vary a bit by card issuer. There are two basic ways to set a monthly minimum payment: Percentage + Fee. This means your balance is multiplied by a percentage (usually 1% to 3%), then any fees are added (including late fees).
Each time you make a minimum payment, almost all goes to pay the interest incurred and only a tiny fraction goes to pay the purchases you charged (the proportion depends on your credit card rules). And each month (if you don't add any new purchases) the minimum amount due falls by a similar small fraction.