The muscle soreness in the arms that you reported might be related to cervical spondylosis.
Cervical spondylosis is a condition in which there is a degenerative process in the joints between the neck spinal vertebrae. This process might slightly decrease the space where the spinal nerves leave the spine. This might put pressure on the nerves causing pain along the nerves. When the vertebrae in the neck are affected, then the nerves responsible for the arms might present the pain. This pain might seem to originate from the arms, the shoulders or the neck itself. Giving the fact that you eased the pain in the neck and the shoulders when you visited the chiropractor, cervical spondylosis is likely to be the right diagnosis.
You might want to visit an orthopedist for a physical examination and an X-ray of the neck part of the spine. Physical therapy might be recommended. The chiropractor might also help you if s/he concentrates on the neck. Meanwhile, avoid putting your neck and head in one position for long periods (for example, watching television or working on computer). Try to change the posture for every 10 minutes or at least give yourself a break a couple of minutes after each half an hour of work.