So you've got 3 options
1 - Someone is actually saying theses things / the noise is present in real time... In which case you should be able to track them down. Whether it's a person or a television show your neighbor is watching, the noise has a discrete source.
2 - Intrusive thoughts / memories (not actually happening in real time)
3 - Auditory hallucinations... (Not actually happening, although one is hearing them in real time)... Which can have many, many causes. From medication, to an injury, to a medical condition (such as a tumor, or mild seizures), to a hallucinatory disorder (there are many types, schizoaffective is one of several... some are caused by leisons often following stroke, others by sleep disorders / the brain is essentially catching up on missed sleep while awake and still partially dreaming!), some are caused by damage or infection to the ear or inner ear (endaural phenomenon).
None of these 3 things are PTSD, although the second one is a symptom of PTSD, that would be memories of things that had once happened and are not happening now... Intrusive thoughts are a symptom in about 50 different disorders... It's not something that helps identify any specific disorder.