Some days i am fine.. other days i feel like i have a big ball of something stuck in my throat.. what can it be?

Multiple causes: Irritation in the back of the throat can occur from post nasal drip while horizontal. This can be caused by seasonal allergies, sinus problems, air quality... Reflux disease (GERD or Heartburn) can also cause this problem if gastric contents come up the esophagus into the throat while sleeping. Simple changes in eating time, elevate the head of the bed, weight loss can dramatically improve things