Chest tightness and shortness of breath caused by dieting are usually recovered in about 3 days after normal eating if they are caused by simple dieting. If the chest tightness and shortness of breath is caused by using diet pills during dieting, it usually recovers in about 1 week after stopping the use of the pills. If the symptoms persist/aggravate, you should go to the hospital as soon as possible to check, for example, whether myocardial ischemia has occurred. If you take diet pills at the same time as dieting, it may stimulate the gastrointestinal tract and cause abdominal pain and diarrhea, as well as nausea, vomiting and loss of appetite, but you will recover in about 1 week after stopping the medication, because the medication is gradually metabolized from the body and will relieve the symptoms of chest tightness and shortness of breath. In addition, some “diet pills” may also cause heart muscle damage, and even myocarditis, so try to lose weight in a formal way, such as specialist weight loss clinics.