Condensation behind furniture is very common, as it blocks heat so, if external, that part of the wall is colder, so condensation forms on it.
If the wall is damp, the furniture impedes air circulation so it does not evaporate off the wall and into the room. To my eye it looks more like a damp wall. The foil test will tell you which it is (might be both)
Mould spores are everywhere in the world, all the time, and will grow if moisture and temperature are suitable, so concentrate on getting the water down.
If you need to find a tradesperson to get your job done, please try our local search below,
or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Please select a service and enter a location to continue...
Are you a trade or supplier? You can create your listing free at DIYnot Local