Oxypowder can help with candida also long as it is only located in the intestinal system. There are many causes of a stiff neck some of which are various types of infections.It could also be a type of injury or maybe some more serious. The best thing probably to have yourself evaluated by a naturopathic physician who is able to properly diagnose what the actual cause of your stiff neck. There are products that you could add to your daily regimen to help your body rid itself of candida. You can add a good priobiotic, and a parasite cleanser. The priobitic that I have ussed will great success is called Latero-Flora. The company that makes the Oxypowder makes two products that can help your candida which are Paratrex and Organic Oregano Oil.