Why do you think my mature cat Meows so loud in the middle of the night? Has anyone ever experienced this before?

In the hours between 1:00AM and 4:00AM my 14 year old female chonky monkey cat Meows so loud like she is crying for help! EVERY NIGHT! So I get up and put her on my bed and show her affection then she is fine sleeping at the foot of my bed. But I wonder is she in pain? Does she have an underlying health problem that's causing her pain like cancer or something?? Or is she just lonely?? And wants some attention?? Anyways it's happening every night and snuggling with her usually calms her down....What do you think? Have you ever experienced the same thing with your cat?