Pain is an experience, not a physiological description. When you stub your toe, you feel pain, not a description of the biological mechanism.

No. The signal is not the pain. Pain signals are not feelings of pain. Pain happens in the mind.

Right, the mind processes it, and in turn does something, analogous to how computers process signals, and in turn do something.

Maybe analogous, maybe not. Analogy is in the eye of the beholder. There's no law of the universe that says that consciousness is equivalent to computation. Maybe consciousness is an emergent property of biological systems, along some dimension currently unknown to us.

Which is my point.

Consciousness and computation are entirely up to what we define these words to mean. At some point we have to settle on a satisfactory definition of consciousness that fully differentiates it from computation, or they’re left with at least some overlapping (analogous) meaning.

If we dismiss consciousness as currently unknowable us, and thus undefinable (as your statement about dimensions alludes to), then how can we say assume with certainty, that we haven’t already achieved conscious AI?

Does it feel pain? I think not.

Then what is pain, and how do we make computers artificially feel it?

If we knew the answer to that, there would be no hard problem of consciousness.