My guinea pig is acting strange :/?

That chattering sound is usually a warning sign that they don't want whatever is happening. Is she injured? Has she jumped out of your arms lately or fallen anywhere? You may want to give her a rest and monitor how she is doing. Be sure to check if she is eating and drinking--if not, or if it has decreased, she has internal pain and will need to see a vet. If she continues to seem in pain the next day or so you should bring her in for a check up. Be aware that even a small jump or fall could cause an injury to her limbs or back.