If your breathing muscles are compromised and you are having difficulty breathing will your spo2 saturation be normal or low?

Either. Will depend on the compromise. You should watch it by using a pulse oxymeter at night if goes below 90% , get a lung doctor to evaluate you. Likely will need an overnight oxymetry or ideally a sleep study to check for hypopneas & apnea events (stop breathing while asleep) then if thats the case will need a CPAP or other machine to assist your breathing at night.