I started taking vit D3 1000 IU and B12 1000 mcg ( 3-4 days ago ) and now I have sore breasts . I didn't have this in a long time and the vitamins are the only change I made . Can be from the vitamins ?

To determine if these are the culprit... you'll have to stop them both, wait at least a week, and restart one, take it daily for at least a week, and if no side effects, add in the second.

1000IU of D is a very small dose. The B12 is not large either, as only about 13mcg of that 1000mcg dose is absorbed.

Patients who are very anemic may develop low potassium at the start of B12 shots or oral...because the B12 stimulates red blood cell formation to fix the anemia as a priority. But that usually is a short lived side effect and doesn't happen for everyone. (fatigue, muscle weakness or cramping).

But I just started them and I would hate to stop, I need these vitamins. If this is from them, will probably stop after a while , when my body adjust to them ?
And I'm all jittery inside, little dizzy too today ( after my third b12 pill ) but I had that problem before these pills.
When I woke up in the morning I take the b12 on empty stomach, but that's hours before I get up ( 3-5 hours before I eat anything ), is that ok ?

Yes, you are taking them correctly.

No one has posted here in my recollection with your side effects however. But people are all different, and that is not to say that the B12 may be adjusting your hormones somehow. Are you pre-menopausal or going thru menopause or after?

1000IU of Vit D is not alot. The 1000 looks like alot, but in reality it is 1IU D is .025mcg (micrograms) So 1000 is 25mcg or .025 milligrams. So we are talking about minute doses. (there are 1000 micrograms in a milligram.

http://www.thecalculatorsite.com/art...-ui-to-mcg.php

I'm probably pre-menopausal ( I'm 47 ) and I take bcp pills for years.

Caffeine is really a big culprit in breast soreness and cystic type breasts.

I found that after the menopause, I had tremendous relief from the aching myself!

I think any woman on hormone drugs, could have breast tenderness any time!

So would it be OK if I continue taking the vitamins and just wait and see about this " side effect " ?
Thank you so much !

Yes, I would continue... if the breasts get worse, then consider taking a break.

I am by no means and expert and my research is minimum...I have read that taking B12 alone isn't the best for some people...it might need to be a b complex or two b's...I agree with MrsD, and I agree with you, keep trying for a bit longer, if the discomfort continues a break to see if it's the vitamins or not....hope you feel better....keep up the fight....

Birth control pills disrupt folate so adding in a good B complex like Enna suggest may be helpful. Folate and B6 serum levels are impacted.

http://www.ncbi.nlm.nih.gov/pubmed/952302