Can I freeze undercooked (pink) chicken to finish cooking later on? Cooked chicken breasts, thermometer was not working properly, so I thought they were done. Took out, let sit few minutes, cut open to discover most of the meat was slightly pink. I cut it up and froze it in small batches to use in the the next week or two. I had second thoughts about freezing in the first place but could not find any answers. Can you help?
It is entirely fine! The only thing I would worry about is when you are re-cooking them. Let them come down to room temperature before you throw them on the heat, otherwise, you'll get overcooked/burnt edges and a barely cooked centre. I would just be wary about keeping them in the freezer for over two weeks, not for health and safety, but just for taste and culinary standards. 

For when you take them out for your meal; enjoy!