Hello and welcome to health care magic, I am sorry that you are not feeling well.
There are different medical conditions that can cause the symptoms that you are describing. You stated that you faint when you stand, it is not entirely clear if you mean that you actually lose consciousness or if you feel dizzy/lightheaded.
Standing successfully requires interplay of the amount or volume of blood, neurological factors, hormonal factors and factors related to the blood vessels which compensate for the pooling of blood in the veins that occur as a result of gravity when a person stands.
Some of the medication taken for high blood pressure
can increase the risk of the blood pressure dropping on standing. Other causes include dehydration
, problems related to the heart such as a abnormal heart rhymth or heart valve problems , diabetes or problems related to the nervous system.
Shortness of breath
after a short distance , palpitations and chest pain
can possibly be linked to any issues to the heart ( structure or function) or lungs.
Some persons with anemia can have shortness of breath along with dizziness, palpitations and chest discomfort
So therefore some of the possible causes include: postural hypotension
, heart failure
, angina , asthma, COPD, arrhymthmias ( abnormal rhymth of the heart), anemia
You need to see your doctor, he or she will take a history to determine the extent of the problem, the exact symptoms you are experiencing, what makes them worse and what results in an improvement. He or she will likely check your blood pressure on standing and lying down, check your ears if you describe any symptoms of vertigo ( if you do may check to see if induced by certain positions), check your pulse ( rate and rhymth), check to see if you are pale and listen to you chest for any abnormal sounds.
Investigations may be ordered based on the findings.
I hope this is helpful to you , wishing you the best