Wifi not working

My iPhone 4s recently stopped connecting to Wifi and I was getting the "greyed out" problem. I researched it and found that putting your phone in the freezer for a few minutes seems to help, so I did that. After freezing for a few minutes, my phone connected to Wifi for a very short time and then kicked off once again. I have now frozen it three times and still no Wifi. What's going on? Is my iPhone shot?