Are there channelopathies linked or associated with CFS?
At the very least associated, yes.
There's increased acetylcholine and adrenergic receptor antibodies in ME/CFS. Multiple studies can be found Googling this.
Aside from the muscarinic and adrenergic receptor antibodies (reported by many here), the following are others that have been reported by some in this forum: Voltage-Gated Calcium Channel, N-Type (VGCC), Endothelin-Receptor-A (ETAR), Angiotensin-II-Receptor-1 (AT1R), N-methyl-d-aspartate (NMDA) receptor, and GABABR (gamma-aminobutyric acid B receptor).
Aside from that, Enterovirus B infections are associated w/ ME/CFS, and some have cell tropism for natural killer cells (like Coxsackievirus B4). I suppose this means there's a chance that this could result in the calcium dysregulation via the decreased TRPM3 receptors on NK cells that Pyrrhus mentioned. The CVB's cleave proteins in infected cells that can mess w/ cell surface receptors and their functionality.
But that all sounds like a reach.