Hello Mr. Pradeep, Faintness, tiredness and inability to concentrate with altered behavior raise the possibility of reduced blood sugar levels (hypoglycemia). These can be related to long gaps after food. At times, similar symptoms may occur immediately following food too. Alteration of different salts (sodium, potassium, calcium) also may lead to alteration in thought process. Where is the chest pain located? What is its relation to exertion? Central chest pain over lower end of breast bone with spread of pain on to left upper arm and forearm needs to be investigated on the lines of heart disease (coronary artery disease) though your age is against that possibility. Electrocardiogram and enzyme tests will help to sort out this possibility. Please discuss your problem with your family physician. Wish you all success in finishing your studies soon and thanks for using Healthcaremagic.