During the first few days, tightness in the chest can occur. This shouldn’t be so severe as to cause discomfort however it should be expected. Tightness in the chest can result from the shock to your lungs as they are recovering from the stress caused by smoking and possibly a mechanism to aid in the draining of the lungs from mucous and as it begins to clear tar deposits. Some speculate that this might also be a result from the “emotional loss” or other psychological symptoms. Try to take deep breaths during breaks and drink lots of water. Exercise can help as well.