I have no idea about VM I'm afraid - perhaps someone else can advise on this. Have you tried TENS for pain relief? or had any hands-on mobilisations to help your neck? I find a gentle self-mobilisation technique quite helpful when my neck pain onsets or I wake up with a lot of stiffness/headache. If you roll a towel so it is long and thin and you can grip both ends in your hands, wrap the towel around your the middle of your neck (more towards the base). Looking straight ahead, with your hands pulling the towel quite taut and making sure your hands are level with your eyes, keep your chin tucked in and slowly look back towards the ceiling. At the same time, pull upwards with your hands following your eyes to keep a gentle pressure on your neck as you're moving. Try doing about 10 of these slowly and then re-check your neck movement (do whatever movement usually causes pain) to see if it has eased at all.
Some gentle piriformis stretches can be found here - they will be painful but it's important to stretch the muscle in order to reduce the buttock pain and leg symptoms (if these are coming from piriformis being irritated) Piriformis Stretches - Spinal Health Care