the brow and the back pain are probably not related. I dont suspect anything serious.
The most common thing is something we refer to as ocular myokymia. Simply put, this is a very common, benign twicth of the lid (upper or lower) and is often a result of increased stress, decreased rest or sleep, or increase in caffeine intake. It is temporary and usually gets better on its own as you get more rest, less caffeine intake or better handle the stress in your life (if you cant reduce it).
Another things is something we call blepharospasm which is actually a very bothersome, obvious, not so subtle involuntary blinking and eye closure (versus a much more mild twitch) and this can be related to ocular irritation / dry eye syndrome as well as generalized dysfunction of the nerves that close the eye. This tends to be bilateral.
Like I stated, most often the twitch is quite benign and is called ocular myokymia, and resolves in a few days. Get extra rest if you can. Since yours has been ongoing a while, you should be evaluated by your doc, they may consider a CT or MRI make sure there is nothing pinching your nerve. I hope this helps. If you have any questions, please let me know
PS Here is some more information for you: