If I am the observer then who creates these thoughts in my head? Sometimes, I have up to 4 different personas in my head talking to each other about everything that happens in my life and all the ideas that I find interesting. Occasionally they remind each other that they are not real and then my head goes silent for half a minute. I am healing from my OCD significantly by grounding myself and accepting that my intrusive thoughts and thoughts in general are just thoughts and that I dont have to associate with them, but who creates them then? I feel that certain thoughts, which are neither compulsive or random like the ones I used to write all this stem from that inner me controlling them so I can talk in my head but Im unsure.
it sounds like you are not fully in control of your inner monologue which i have struggled with in the past and can give you some advice to help.
the 3 parts of the mind as accepted in general psychology are the conscious, the sub conscious and the unconscious.
the conscious mind is what generates your intentional inner monologue. when you think of a sentence and "hear" your thoughts in your head, like when reading a book. that's the conscious mind at work. when you think to yourself "I'm gonna go to the store" and then you do. that is your conscious mind at work.
the subconscious is a deeper level of your mind where ingrained behavior is stored. for example when a fast food worker hands you your food and says "enjoy your meal" and you reply "you too" even though that does not make sense, that's your subconscious mind recognizing an ingrained pattern of speech and momentarily taking over to reply on the consciousness behalf. your subconscious also plays many other roles in your emotions, dreams, involuntary reflexes and dreams.
your unconscious mind is the deepest most buried part of your mind. it holds your emotional trauma, PTSD, and evolutionary animalistic instincts like the need for sleep, food, water, and the desire to reproduce.
what I've noticed in my studies is that when you lose control over your inner monologue and start to have multiple "personas" in your head, as you say, its because of a lack of stress and a lack of (mindfullness) that needs to be trained like a muscle. to train your mindfullness you need to practice throughout the day to be consciously aware of what your feeling, why your feeling it. set a timer if you have to 3 to 5 times a day take a moment and a deep breath and consciously think. " what emotions am i feeling right now? why am i feeling this way? am i ok with feeling this way?"
along with this take time to distinguish between your conscious thoughts you are willingly producing yourself and the thoughts your subconscious is pushing to the top. think to yourself " these thoughts are my subconscious trying to tell me something but they are not what i am choosing to activily think about in my upper mind"
some research has suggested that naming your brain helps with this process. it helps separate the thoughts from the primary observer/ conscious mind (you) and the personas/unconscious mind. after you name your brain, talk to it, when you notice your feeling angry and having thoughts from these personas that you don't know where they are coming from. ask your brain "what's up dude?"
incorporate this into your mindfullness training and overtime you'll find you've strengthened your internal monologue and solidified your self image as to who YOU are.