Well, valerian is a anti-spasmodic. You might want to be careful as it might make you groggy.

Here is a link that might be useful: valerian info

HEAT ...

Try massaging infused arnica oil into the area. It is great for muscle pain. You might also look into some fresh skullcap tincture or kava tincture for anti-spasm. Get these from a reputable source and don't bother with capsules and do the research to make sure it won't interact with any meds you are on. Tiger Balm or some other sort of heating balm would be nice too. Consider seeing an acupuncturist also. You can see amazing benefit quickly with acupuncture. Ask your physical therapist about gentle range of motion exercises you can do to prevent the spasms from getting worse through non-movement due to your pain.

Thanks people, this has been really useful!

I have had recurring problems in my neck and shoulders and after years of seeking help through Chiropractors etc, I happened across a book at Barnes & Nobles which has been the most helpful by far. It is the "Trigger Point Therapy Workbook" by Claire Davies It goes into detail explaining how certain activities can cause trigger points in the body which cause certain muscle groups to act up. My muscles tend to contract and stay that way so I bought myself a Thera-cane tool which makes it easier to reach hard to reach places myself and thus not have to depend on someone else. Now I can work those trigger points with the theracane until I get relief. Heat packs may help also + I think BLOO GOO with emu oil works pretty well also for pain relief. Getting at the root of the problem tho' by addressing the trigger points themselves has been the key to breakthrough for me -the surprising thing is the trigger points are often in a different spot from where you feel the pain.
I am not trying to sell anything and have no stock in any of these products - just sharing what I have found to be helpful in my own case.

I have tried everything from doctor prescribed rx's to almost every herb from a-z. First off, please be very careful in general listen 2 your body! Especially when on prescription drugs and trying/introducing herbal remedies into your routine. every BODY is different and only u know what does and does not work. Heat sometimes helps, but for me I cannot tolerate heat because I have M.S. I find great results from cold packs. I have also how found great results from certain herbal tea mixtures.