I need help to find out why my feet are always freezing cold ..and why it happens?

Google "Raynaud's": A lot more information and exam would be helpful, but the majority of people with that presentation have over-reactive small vessels of the limbs (especially young females). I would see a doctor to make sure - good pmd should be sufficient. If it is raynaud's, no treatment is needed -just avoid exposure to cold: use warm socks and mittens.

Blood vessel issue: If you have cold feet and pain then you need to see a vascular surgeon. This could be a very serious problem.