I imagine you thought the worst, with the pain being where you describe, so I'm pleased you've sought medical advice.
The Paracetamol will help inflammation but you may have muscle tension from over-working the muscles of the chest and shoulder.
Do you drive for long periods using one arm on the steering wheel or does your occupation involve a repetitive motion involving one shoulder more than the other?
You may have read my answer to similar queries but the advice would be the same. Make sure your tea and coffee intake is minimised, as these drinks deplete magnesium which helps relax tense muscles.
If you choose to add some extra magnesium into your diet, simply eat lots of plant foods (especially anything green or brown) and perhaps add a magnesium supplement, 200mg twice a day.
You can also try a magnesium spray which I cannot vouch for but have heard many good reports about.
If the pain is affecting your sleep, try some Valerian as it has been used to aid sleep, relieve pain and relax muscle tension. Use a liquid as it'll get into the system much faster. Just be aware it doesn't taste too good, so perhaps dilute it in a touch of fruit juice.