Hello and welcome to health care magic,
As you rightly opined it may be related and it makes sense to do further testing and evaluation.
You need to get an audiometry
testing done and also take a CT of the temporal bones and get back to me or any ENT with the reports as soon as possible.
It is however unlikely that a cordless phone causing any of these problems as the waves are not like mobile phones.
Hope this helps
Dr Sriram Nathan