This can sometimes happen when enhancements have been removed too.
The natural nail has been protected to a certain degree by the nail enamel in this case as well (as the enhancements in other cases) and can need to adjust to having no protection when the coating has been removed. Usually the person is a longterm nail enamel wearer. The nail needs to have the natural oil replaced and to 'waterproof' itself and toughen up again so to speak.
Some peoples nails are more sensitive than others which is why some 'feel' this ache and some don't.
It is good to use solar oil and a product like 'toughen up' natural nail strengthener when enhancements have been removed to help build up the protective layer again and to avoid the sensitive stage of one or two days - sometimes longer - that some can feel.
I get this too.
My (own personal theory - having no medical basis) is this...
I wore coatings (of polish) on my nails continually for so long, that they had no (or not enough) natural oil on the nail plate. So when I take off the coating they get the opportunity to "breath" - the oils have to oppertunity to moisturize the nail plate, and therefore, the nail plate gets to expand a little which pushes it into the side walls and causes pain discomfort.
The best analogy I can give for this is this; you know how wooden external doors and gates get harder/stiffer to open when it rains ? - because the wood expands a little due to the increased moisture levels (osmosis) I think it's kinda like that.
While you are wearing any coating... the oil and moisture content in your natural nail plate actually increases.
When you remove the enamel, you remove all of that built up moisture and oil. Depending on the removal solution and technique, you will also remove a lot more oil and moisture from the nail plate above and beyond the extra that had built up.
This can make the plate far less flexible and almost more 'sensitive' to touch until the oil and moisture content returns to normal.
The only other reason I can think of has to do with Area 51 and probes... we wont go there. :beam: