I would avoid the option of the injection as they have a poor success rate and can be painful.
Orthotic insoles in supportive shoes (can be trainers) are essential and persevering with the calf stretching exercises.
The most useful I found was to stand on the balls of your feet on the edge of a stair tread( facing upwards) with your heels hanging over the edge. I held on BTW!
Let one foot drop as low as it can , and raise again about 20 times, then the other, then both.
Rolling your foot over “prickle balls” is also good, but I found it uncomfortable.
Stand with your feet close to a piece of furniture or a wall and stretch each foot upwards keeping the heel on the ground.
I saw a podiatrist every week for shockwave therapy too which may have hastened my cure but it still took a good 6 months.
You have my sympathy, but it DOES go away.