Hi..
Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concerns..
As per your complain smelly straw coloured discharge from ears along with irritation and itching seems to be due to 
ear infection and as it was present even before wearing  it does not seems to be due to hearing 
aids and there is a possibility that you are wearing the hearing aids that is continuously being infected with the discharge leading to persisting infection..
I would suggest you to consult an Otolaryngologist and get evaluated and a thorough clinical evaluation and investigations like swab culture of discharge can help in diagnosis and treatment can be done accordingly..
You can be advised a course of 
oral antibiotics, anti-inflammatory painkillers and oral and nasal decongestants..
You can also be given antibiotic and 
analgesic ear drops..
You should limit the time duration for wearing hearing aids and always disinfect them before wearing till the infection is resolved..
Hope this information helps..
Thanks and regards.
Dr.Honey Nandwani Arora..