Rounding of the shoulders and protrusion of the neck is certainly pertinent with the prevalence of smart device and computer use. It can also occur from tightness/weakness of various muscle groups such as your pectoral and shoulder retractors. Forward positioning of the neck can also be due to alterations in neck curvatures.
I would suggest seeing a Sports/MSK physician or a physiotherapist who can assess you and advice what might be going on. You might benefit from a neck X-ray and depending on other symptoms - other investigations. Treatment can be as simple as stretching off some muscles groups or strengthening others.
You might need to have your workplace assessed and other habits/practices discussed.
Differentiating between the two depends on your clinical symptoms and presentation and so too does your treatment.
I hope this helps.
Bw
Dr Dinesh