The world number one was diagnosed with the condition in February after his mother-in-law spotted a rash on his body.
Murray has also struggled with an elbow injury and flu in 2017 and it has affected his form on the court with surprise defeats to Fabio Fognini and Borna Coric in his last two tournaments.
The 30-year-old faces Russia's Andrey Kuznetsov in the first round of the French Open today.
And Henman thinks Murray's woes this season stem from a lack of rest after a mammoth effort to overtake Novak Djokovic in the tennis rankings.
French Open 2017 pictures Mon, May 29, 2017
Pictures from the French Open 2017, the second tennis Grand Slam of the year.
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Garbine Muguruza playing at the French Open
What he did last year and the amount it took out of him, he didn't really get enough time off
He told Express Sport: "Andy's had a difficult time, I just want him to be fit and healthy because he can then build some momentum into his game which hasn't happened this year.
"What he did last year and the amount it took out of him, he didn't really get enough time off before going into his training block in Miami.
"I'm sure that is a big reason why he got the shingles, his body was just exhausted.
Andy Murray starts his French Open campaign today
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"Shingles is not something you take lightly and I don't think he's necessarily properly recovered from that.
"To practice, train and build up momentum in tournaments at his level is very difficult and he's sort of been chasing his tail most of this year.
"I just want to see him be healthy in Paris and whatever happens, happens and hopefully that will give him a foundation going into grass."
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