Difficulty breathing all the time but, the er says my oxygten is good at 100, blue fingers what steps should i take?

Blood gas test?: Did the er tell you your oxygen level was "100" based on a pulse ox or an arterial blood gas analysis (where a needle is placed in an artery and blood is collected and analyzed)? You need a blood gas analysis and likely other tests as well to determine your diagnosis. You should be evaluated by a lung specialist and you can be sent for the proper testing. Return to the er if your symptoms worsen.