Hi. Atorvastatin is standard bad cholesterol that is LDL cholesterol lowering drug. If taken alone that to say without aspirin combination it is unlikely to cause any chest discomfort. Rare side effect is hepatotoxicity which can presents as nausea upper abdominal pain and raised liver enzymes on testing blood sample. It is also known to cause muscle pain and cramps although that too very rarely. However it is better to consult your doctor to know the reason for your symptoms as atorvastatin is unlikely culprit. Regarding taking atorvastatin at night there is absolutely no harm with that as it need not be taken in the morning as such. Wish you good health, take care.