Everyone is different I have been on Lamictal for 2 years, did not have muscle pains, or any of the major side effects. Every medication has side effects, by law they have to be public, many of the meds have the same or similar side effects, some take time to go away, and perhaps your mix you are on may be interacting, I would talk my pdoc if I were you, maybe somethings can be changed, I personally wouldn't give up on the Lamictal, until you discuss this with your pdoc.
I wish you much patience with this, it gets frustrating I know (from my experiences) but try to hang in there and discuss with your doc if there other options/alternative meds that may help you and yet have the least amount of side effects.
Some side effects can be mild or in time wear off, we also have to ask ourselves if the side effects are tolerable vs living with the disorder, I chose living with some of the mild ones, I use to get all uptight when I would sit and read side effects and it use to discourage me from meds, but I got tired of feeling so unstable so I said "the hell with it" I'll give them a try. Sometimes we just need to give things a try, otherwise we may be missing out on an opportunity, I made that mistake if I had just taken the Lamictal instead of Depakote 4 years ago I could have saved myself some grief, Lithium worked great for me when I was agitated, once that left I switched to Lamictal for it's AD property cause I am more of a bipolar that suffers with extreme depression. Lamictal isn't an AD but a mood stabilizer that address bipolar depression quite well. I hope I haven't ranted on too much, and I hope I was of some help to you.
Please stay well,

DE

In giving advice seek to help, not please your friend
SOLON