4 lb Shoulder Pork Roast
Yes, it is still safe to eat. If the meat itself has been at room temperature for two hours, it is generally unsafe to eat. Your meat never reached room temp, even the meat on the outside.

It may take 24-48 hours for your roast to pork roast to thaw in the refrigerator. Another option you have to speed up that process is place the roast (still wrapped) in a bowl and fill with warm water. Once the water turns cold, change it for more warm water. Do this as many times as necessary until thawed, or do it 5-10 times and refrigerate overnight.