I would like to know if this is retaliation or if I'm reading more into it.?

I filed a complaint against the Customer Service Manager who is friends with the HR Manager. I am the purchasing Agent at my company. Three weeks later the HR Manager moved my desk to the front door and made me the receptionist, I have to however continue to preform my Purchasing related duties. My back is to the door at least 50% of the time and I have started to get neck and shoulder pain from the constant twisting and turning to receive guests. I was essentially demoted to receptionist but must also maintain all the other duties I had prior to this move. Could this be considered retaliation for my complaint? The company has been hiring employees for various other departments including Customer Service so the argument that there is an employee freeze is not one that can be used for not hiring an actual Receptionist.