Your problems seems to be related more to increased tenderness of the breast due to hormonal
changes during your period irregularities.
Another factor could be any possible pulmonary problem, that could be identified by consult a pneumologist (physical examination or X-ray).
With regards to vitamin B12 deficiency
, I would suggest to consult a neurologist
to do the conductivity or other tests for nerves function.
Wish you good health!