I have been using medical cannabis for several years now, and I do find it very helpful.
My experience, which of course may be entirely different from yours, is that it works a lot better on some kinds of pain than on others.
I don't know where you live and what is available to you. Where I live, it is legal for both medical and recreational use, which makes it very easy. If you have the ability to go to a dispensary and have a one-on-one conversation with someone there who is very knowledgeable about the products they have, that is the best thing. There are so many different strains and strengths that you don't just want to buy something and try it without knowing what you are getting.
I went in to my dispensary and told them in detail exactly what I was looking for. The person I spoke to was very helpful, asked the right questions, and ended up selling me something that turned out to be just right for me. Since then, each time I go in there I have a similar experience. If you have more than one place to choose from, be sure to go to a place where someone can talk with you about your specific needs. And keep in mind that the exact strain that helped you may not be available the next time you go in to get it. (At least, that has been my experience). But you can usually find another that will do the same.
There are strains that will relax you, others that will give you energy. There are some that are far better for pain than others. And make sure you let them know whether or not you want to have a "high" from it, and to what degree, because there are strains that will ease pain without making you fall asleep or get so high you can't live a normal day.
Another thing to consider is the form you take it in. Smoking is the most common, but it's of course terrible for your health, even if all you do is a little bit. There are edibles and tinctures and drinks you can get these days, so consider all of those. Edibles will, of course, take a lot longer to take effect since they have to go through your digestive system first. Tinctures will take effects in only minutes because you hold the liquid under your tongue and it is absorbed into your mucus membranes.
I found that over time I learned exactly how much of which kind of strain, and which delivery system, was right for any given day or kind of pain. It takes experimentation but if you get results it's worth it.
Be aware that some doctors will not condone it, and you need to be careful with what you tell to whom because of that, even if the use of it is legal where you are. I have had a doctor tell me they will no longer see me as a patient because I started using cannabis.
Cannabis does not interact badly with any other medication, contrary to what
@ayassresearch says above. Of course, if you are taking a medication that makes you sleepy and you take a strain of cannabis that does the same thing, it will increase the sleepiness. But there's is no known bad or dangerous drug interaction between marijuana and any other pain medication.
As for the type that is most effective "still being studied", as ayssresearch said, this is also not really true. For one thing, there is no one size fits all, and there is not ever likely to be a particular strain that works best for most people with fibromyalgia, just as there is no one thing of any other kind of treatment that works best for people with fibro. We are all different, and for some people marijuana doesn't help at all. Any "study" into this is primarily being done by individuals who are doing their own experimentation, not by the scientific research community.
