It moves through stages
Frozen shoulder typically goes through a painful 'freezing' stage, a stiff 'frozen' stage, and a gradual 'thawing'. Physiotherapy is tailored to the stage — gentle pain-respecting movement early, then progressive stretching and strengthening as it settles. Pushing hard in the painful stage backfires; a physio knows the difference.
Consistency is the treatment
The daily home exercises are what restore range of motion — the occasional session alone won't do it. A physiotherapist sets a programme you can actually keep up, adjusts it as the shoulder changes, and keeps you moving through a condition whose biggest risk is giving up because it's slow.
When it's not just a frozen shoulder
Shoulder pain has many causes, and some need imaging or a doctor. A good physiotherapist assesses properly and refers on if the picture doesn't fit — rather than treating everything as the same problem. Diabetes and thyroid conditions also affect frozen shoulder, which is where coordination with the doctor matters.