Usually, very vocal hens are healthy, just loud. But this sound may signify egg distress. You need to pick her up and bring her inside and do a thorough checkup on her.
Just as a doctor does, start at the head, and check eyes, ears and throat. You may need a helper. Use a flashlight to look deep into her throat. and ears. Check for anything that shouldn't be there - crust, gunk, blisters, swelling.
Move to the crop. Check for fullness and if it's hard, lumpy or squishy.
Feel her abdomen. Any swelling or hard lumps anywhere? Look at her vent. Is it swollen and pulsating? Any skin redness below the vent?
For starters, I have a hunch she is in an egg crisis. She could have a stuck egg. Give her a calcium tablet first thing. It will do no harm if this isn't her problem. Just pop the tablet into her beak. If you have no calcium supplement on hand, give her Tums. If you don't have anything, go buy it. It's that important. This is what you should buy.