The best treatment for Restless Leg Syndrome (RLS), weather from narcotics or otherwise, is a small dose of *Tramadol* bar none!!
Do not worry about addiction as its a very small dose that you can come off anytime you are ready and one can use it for up to 30 days if needed. Try the absolute minimum that works for you, that would be a starting dose of 37.5mg-50mg to as much as 75mg-100mg (instant release), more than that you simply don't need unless your looking for a buzz (shitty one at best even for an opioid head). Most people are able to find this medication without too much hassle either from online pharmacies or from your doctor, that is if you can convince him to prescribe it to you.
p.s. Ibuprofen IME has been the most effective OTC NSAID in terms of muscle relaxation. I have also tried the OTC muscle relaxant Robaxin aka methocarbamol not to confused with the (much) more recreational carisoprodol or meprobamate. This can also be found without the acetaminophen and it does the job but from 1 to 10 I would only give it a 4-5, simply ameliorating the pain by no means eliminating it completely as most opioid users expect.