Hallo all,
I hope wise people here would be able to answer my question. Can a cleric with fire domain use his fire bolt domain ability while grappled / pinned / helpless condition?
The Fire Bolt is a "spell-like" ability and as such, it "has no verbal, somatic, or material component, nor does it require a focus. The user activates it mentally". So the only thing you may need to worry about while grappled, is the Concentration Check.
"Helpless" is another matter. While you can still take mental actions, you can fire your bolt. But if you're, say, unconscious, then you won't be doing much of anything.