Well I want you to know I am a long time sufferer of allergies and sinus problems. I have had three sinus surgeries. I have noticed that over the years that when my nose/sinuses are messed up so is my neck. I'm never quite sure which started first though. I would highly recommend going to a chiropractor. After the pain meds didn't work anymore and I found myself nausous with neck pain I decided to see a chiropractor. The relief didn't come too quick but in time I was so happy with the results. Though I went for my neck I noticed that my sinus problems started to clear up. I was amazed. I know it sounds gross but in the beginning after an adjustment my sinuses would clear out with alot of drainage that I didn't even know I had. I used to wake up so stiff and tired, like I had been in the fetal position all night! Now I feel great, honest. I also would highly suggest that you buy a product from a health food store called Natural Calm before you go to bed. It's magnesium/calcium powder supplement. It's very important that you have a good balance of both minerals. One is responsible for your muscles contracting and the other for relaxing. This is something that I found on my own. Most places have samples that you can try before you buy it. You'll find that it helps you to relax and sleep better. It doesn't make you feel drugged or anything just relaxed. Just be careful to start off with a low dose and build yourself up to a normal amount or you'll be sitting on the potty alot the next day! ")
And yes you should use ice on your neck. Heat can cause more inflammation though it may make it feel better. Stretching is another thing you should be doing before bed and upon waking. Take a look on the web for some good neck stretches.
I also use a cervical pillow to support my neck at night when I sleep. It takes some getting use to of but it helps. Make sure it's kind of firm and not the soft mushy kind. I use a firm traction pillow to help stretch the muscles out and take some pressure of my nerves if I feel like it's getting tight. You can use a tightly rolled up towel or a small water bottle behind your neck without a pillow for a few minutes too.
Not sure about the vivid dreams and hot flashes when you ovulate. But anythings possible with those hormones! By chance could all these problems be stemming from perimenopause? Don't know your age but I thought I'd ask.