In the UK there are many, many controllers who are pilots - some with ATPLs flying in command. Of course, you could continue to fly privately too, as do hundreds of controllers.
Your posting makes it sound as if you are idly thinking of something to do "ah, wonder what ATC is like?" It's not easy and should be recognised as a career totally different to flying. The training for professional controller is as strenuous as that for professional flying licences and every pilot I have ever had sitting next to me at work has been amazed at what ATC involves. Most didn't fancy trying it.
I suggest you make contact with ATC at your local airfield - as long as it's a real airport and not a grass field for clockwork mice - and see if you can spend time with the controllers. This would give you a far better insight into the job than anything we can tell you on here.
Best of luck...