Why multivitamins don t suit me.

Hello I am male 35...married..recently I contacted physician..about sensation in bone area of veins and not proper digestion..and 1 to 2 times medium very stool..He prescribed me after report vitamin b12 defeciency for me od 12 tablets and six injections 2 a weak of vitamin b12..I didn't told him I take amexide for last 5 years...will taking both amexide antidepressants and me of 12 vitamin b12 tablets harm me I mean interact with each other? And 4 years back and today also have vitamin d3 defeciency..prescribed 60k ..a week but it starts pain in body and heat sensations even taking low dose 400 iu.why so?multivitamins don t suit me too..chest becomes tight and body too and pain particularly vitamin d3..can I take d3 ..me od 12 vitamin b12 and anti depressants amexide together and multivitamins too?? I take tobbaco daily..and alcohol once a month heavy..doctor also asked to quit tobbaco..