Should a pain point be unique? Not addressed by any others yet, or is addressing a pain point that others are already addressing enough if you have a single differentiator.
The pain point needs to be so strong that the target market is willing to pay to get rid of it. First mover advantage (unique pain point) doesn't mean much if you can't remedy (execute) it well.
Your single differentiator must appeal to the needs & wants of your target market. If it's just something you do differently without communicating the value, it won't earn you any new customers.