Thanks for your question on Health Care Magic.
I can understand your concern.
Your all symptoms are explained with
hypotension.
Hypotension causes fainting tiredness,
chest pain etc.
Common causes for hypotension in young age is decreased oral intake of fluids,
dehydration, heart diseases and infection.
So get done ecg, 2d echo (to rule out heart diseases) and
Complete blood count (to rule out infection).
If all these are normal then dehydration is likely in your case. So drink plenty of fluids orally and keep yourself hydrated. Drink atleast 2-2.5 liters fluids.
For pins and needle sensations, get done vitamin b 12 level because vitamin b 12 deficiency can cause similar symptoms. If deficiency then you may need supplements of vitamin b 12.
Don't worry, you will be alright.
Consult doctor and discuss all these.
Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks.