Is it safe to eat cod that has a pink color?
It is very difficult to tell someone else it a food item is good or safe, and the normal advice, especially with meats and seafood, is when in doubt, throw it out.  In this case, there honestly is too many unknowns.  The wording of the question: 


  it sat in my fridge for a couple days and spoiled i froze it


Sounds as if they fish spoiled, and then you froze it.  Freezing will not reverse spoilage, it will only slow it.  If the fish had already gone bad, it is bad.

On the pink color, you do not know if it was pink before you froze it or not.  That makes it tougher still.  Right off, I really do not know of a reason freezing would cause it to turn pink unless the freezing/thawing help highlight an already existing condition.  I do know though of two conditions which will commonly cause a normally white fleshed fish to be more pink, spoilage, especially in a fish which was not cleaned promptly, is not stored at proper temperatures, and especially if it repeatedly goes from thawed to frozen or partially frozen and only to a soft freeze rather that recommended hard freeze temperatures.  This would be a fish I would consider bad, even if the flesh remained firm with not other normal signs of spoilage.  The second reason is poor bleeding at the time of harvest, which can be an issue with fish like cod.  It really does not have a major effect on taste, but is considered a lower quality fish due to ascetics and likely will spoil faster than a fish which was correctly bled.  These fish would normally be sorted out and sold at a lower price or to processors that will do something like make breaded fish from them.

There may also be other causes, but those are two common ones I know.  Between those, it would simply be wild speculation to guess without the fish in hand to examine it.