How do you approach pain management for a loved one who has difficulty expressing their discomfort?

As a person who has Alzheimer's I think that it is very difficult for me to identify when I am in pain. Recently, I had oral surgery and since then my teeth hurt but I haven't said anything to anyone until today when I told my husband that I was starving. Due to the surgery I haven't been able to eat like I used to and so I just quit eating. No body really noticed until I saw my friend today and she said that she thought I looked cute but very thin. She was right in the 3 weeks since the surgery I have lost 12 lbs! I am very petite so now I only weigh 92 lbs. I hate those nutritional drinks because they taste terrible! My mouth hurts and I am very grumpy! Which everyone else likes to call agitated...but if they felt like I do they would be grumpy too! Hopefully, I will be better soon and be back to my happy self. The point I am trying to make is if your love one is agitated or grumpy they might be in pain. They might have a headache or arthritis and not able to express their deep sadness about how they feel. They might not be able to sleep or rest. Try to be patient and get them some help. Try some medicine or a heating pad. Comfort them with southing music or something that smells nice, all of these things can go a long way to ease the suffering of a loved one. Don't ignore them, don't patronize them, don't pretend that they don't know what they are talking about...we are there! We do feel! @DonnaFA