Three Cymbalta Questions

Can someone who has stomach problems, in my case mild to moderate ulcerations of the stomach lining, take this medication? Will it alleviate stomach pain or add to it?

I would also like to know: Does Cymbalta cause weight gain?

Lastly, is there any indication how toxic this drug is to the liver compared to other SSRIs? For example, do you have to have regular liver tests while on this drug?