Chest tightness,especially when lying down with occasional palpitation.ecg,chest x-ray and blood test are all normal.can it be related to the heart?

Not heart disease: Try avoiding caffeine and see if that helps the symptoms. Drink enough water daily so that your urine is colorless. For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex. Get HPV vaccine.