Hi Shoard83,
I have not tried Baclofen, however, I have tried other muscle relaxants and find them helpful when I have particularly bad neck or back spasm. Some of my migraines seem to be triggered when my back problems flare up and spasm, so the muscle relaxants seem to help this. I was also concerned about whether they could contribute to medication overuse headache (MOH), so I checked with my headache specialist. He advised that occasional use would be fine for me. I try not to take any acute medications too frequently to avoid MOH. I'm not sure if the advice would be the same with Baclofen, or in your specific case, so it is always best to check with your neurologist or headache specialist.
You may be interested in this 1999 study which found Baclofen to be an effective treatment for the prevention of migraine:
http://www.ncbi.nlm.nih.gov/pubmed/10448546
Although Baclofen is a muscle relaxant, it is also thought to have effects on the brain which may be beneficial for migraine. Tizanidine is another muscle relaxant with studies supporting its use for migraine prevention.
Baclofen is listed as a rescue medication for migraine here:
https://migraine.com/blog/migraine-management-rescue-treatment/
Wishing you all the best with your treatment,
Gemma