Can too much b12 supplementation cause liver pain? Gave myself a b12 injection twice in one week (more than normal for me) and now I'm having some pain right below my right rib cage where my liver is. It was cyanocobalamin which the liver has to convert to methylcobalamin. The liver and kidneys together also have to work together to excrete the unneeded b12 so maybe that's causing the pain. Waiting on some blood tests to come back.