This is not listed as a side effect to the medicine. However, sometimes side effects are unique to the individual. Usually if you're going to have side effects to a medicine this will occur within the first 2-3 weeks. If you suspect this is a side effect of the medicine you should consult your doctor.
Of course ProAir can cause a sore throat: http://asthma.emedtv.com/proair-hfa/proair-hfa-side-effects.html. Proventil HFA was the first CFC-free albuterol inhaler that I used. Then, I switched doctors (couldn't help it) and she prescribed ProAir for me. I stopped using ProAir when I realized it was like pouring acid down my lungs -- probably because it has a higher ethanol content than Proventil. (Ethanol is used as an excipient, or co-solvent.) Then, I switched to Ventolin HFA, which is one of the only CFC-free albuterol inhalers and that doesn't contain ethanol -- and at least it doesn't feel like I'm pouring acid down my lungs. Asthalin HFA (made by Cipla, in India) is another CFC-free and ethanol-free albuterol inhaler that I sometimes use, and I even use Levolin HFA (also made by Cipla), which is a levoalbuterol inhaler (generic for Xopenex) that only contains a small amount of ethanol, which is usually tolerable for me.