I have got problems with C5 C6 & C7, the best advise i have ever got before doing any stretching exercises, is to warm the affected/injured area for 10 minutes before hand with a heat bag, this is the only possible way i can do any stretching to that area i mention and i found that it's most important is not to over do the stretching, i have tried doing stretching exercises without the heat before and finished up in real pain.

Brian