"I always say I need competition - I need competition every week," the Portuguese told the Mail on Sunday.
"For sure I'll be back soon," he added.
Mourinho's dismissal from Chelsea ended his second spell in charge at Stamford Bridge.Van Gaal has been under pressure at Old Trafford after a difficult second season in charge, which has seen his team's style of play repeatedly criticised.
The 64-year-old has another year left on his contract - and insisted at the end of January that he wants to stay until it expires.
However, it is expected that Van Gaal will leave at the end of the season.
Mourinho added: "At this moment I don't know where football will take me, because in football you never know. But as a family, our home will be in London.
"No, I am not enjoying it [not working]. I can have my family, I can have my friends, I can have my quiet life, which I also like, and I can have my football.
"I can have everything together and I don't need to give up on one of them.
"To be fully happy I need everything, so I go back to football. I think it's my natural habitat. I have worked since I can remember, and as a manager since 2000."