That's a resounding, "Maybe."
I know developers who dislike all UI work whether browser-based or not. Some of these are primarily Back Ends guys - others (surprisingly to me) not.
I know developers that find ONLY browser-based UIs painful, because browser UIs are, well, you know - browser-based, i.e., not fully compliant with specifications for HTML, JS, and CSS and differently implemented from one browser to the next. These are mostly EVERYBODY. It's gotten better as libraries have stepped in to provide Facade pattern abstractions to shield us from the vagaries of the underlying primitives across most browsers.
IMO these attitudes are not so much Back vs. Front as they are personality-driven preferences. I know people who find project analysis and design painful but love debugging crashes of live production system. I am the opposite. I know others who enjoy all facets of architecture and development. I'm one of those.
The world of IT is wide enough to justify specialization in any number of ways. A priori, it's not unreasonable to postulate a higher probability that Back End specialists might find Front End work more painful than a Front End specialist. However, good IT folks have to be pretty smart and flexible in general. I'm bettin' smart wins out as needed.
Role and personality-driven issues aside, I think Brandon got it rightest: people find stuff outside their areas of expertise difficult (at least at first).