What Causes Uncontrollable Yawning Attacks?

I have a yawning attack come on and it involves my mouth to move open and shut uncontrollable moves I can t stop it until it s over . I ve had this since I was 14 and now I am 34 years old haven t got a doctor to tell me what it is . When the attack happens I m usually asleep and I wake up to feel like I have stopped breathing for a second . Then the attack happens and I cannot stop my mouth flying open .... It s a cough and a yawning attack I dont know how else to describe it ... If anyone could help me that would be great . I m going to have a sleep study test done to check for sleep apnea . Thank you so much .