It depends on why you are in such sad shape. If it’s because of a serious health crisis beyond your control, then you definitely have my sympathy (I had cancer of the esophagus, the operation and chemotherapy afterwards knocked me on my ass! But I survived and am cancer free as of now.) If on the other hand it’s purely from lack of exercise for no good reason, then at least you can fix that...

when was the last time you had a physical check up by a doctor

So do something about it. Or go to your doctor because that seems abnormal.

As others stated, unless it's an underlying illness you have no clue about, the physical health of your body is on you. Covid didn't stop anyone from exercising or eating well. That's like blaming a school for failing you when you covered your eyes and ears during lessons.

That's not mere laziness, that's chronic fatigue. Even the laziest of slob doesn't get tired just by brushing two teeth. Go to a doctor. Or rather, have a friend drag you to a doctor, it doesn't seems like you can do it alone.

So you might actually want to check HOW you're holding your arm. It is totally, 100% possibly to hold your joints and limbs in such a way that you can fatigue and\or stress them accidentally, even if it feels normal at first. If it helps, at least you don't have Ehlers-Danlos Syndrome and actually DISLOCATE the bastard joints in your sleep...