Yoga before bed: Experiment in better sleep

Like many of you, I usually don't sleep very well.
It's not that a don't get enough sleep, it's that I can't shut off my mind and I can't seem to find the right positions to sleep in, leaving me exhausted from tossing and turning. Other mornings, I'm worn out because I slept wrong and end up with shoulder or neck pain, or both, coupled with a headache.
To combat this constant issue, I decided to try yoga before bed. A friend suggested it awhile ago, but I didn't seriously consider it until recently.

The Child Pose is my favorite because it is so relaxing and just plain feels good.

I found a good video of basic moves that even the least balanced or talented person can do -- that would be me.
After only doing yoga prior to crawling into bed for one week, I haven't seen an immediate difference.
After the first night, I woke up refreshed and ready for my day. However, my day then drained me exponentially.
After the second night, I slept a little better and felt pretty good in the morning. I didn't hit snooze 10 times before getting up.
After the third night, I could tell I slept quite a bit better than normal, however I'd slept on my side and I ended up with a sore neck that day.
I skipped day four as an experiment and found the next day I woke up groggy, sore and cranky. Plus, I'd slept on my side again.
Day five, I did yoga, and the following morning I woke up less groggy.
Yesterday was day six. I think, perhaps, one needs to incorporate a couple different strategies with yoga.
Take this morning for an example. I did my yoga last night, but I slept wrong and have a terrible pain in my left shoulder.
I have a couple thoughts in mind after watching a few other videos.
Yoga is also a type of meditation. I need to do a bit more reading, but my main goal is to take this as a relaxation of the body and mind, not just the body.
If I can't turn off my mind at night, I won't be able to relax. Duh, right?!
I've realized I also need to make a conscious effort to change my sleeping habits. For example, I know I always sleep better when I lay on my back, yet I still sleep on my side. Why? I've always done it. But now I need to change it and sleep on my back.
I also need to focus on my intention while doing yoga. So far, I've focused on doing the poses correctly.
Tonight, which will be day seven, I will focus on intention and sleeping on my back. We'll see how this goes.