I will put my two cents in on this one. I never thought I would have heart issues at a young age but I do. I wasn't born with heart issues my genetic hypertension finally showed its ugly face.
But it is true it could be anxiety, stress, plurisy (fluid) and even a gas bubble. Had them they can hurt like heck. Insomnia can occur for many many different reasons. The food we eat, stress, bp and so many other things.
Making an appointment is your best option let a doctor listen to your heart or run a mild EKG on you to be safe.
Hope you make progress