Thanks for consulting HealthcareMagic!
You mentioned that "if I press the corner of my left eye it is quite sore", this may be because of a stye
which is yet to erupt fully. However, there may be other possibilities as well. Physical examination is mandatory to assess this. Sometimes, external muscles surrounding eyes may also be little painful because of this or due to refractory errors. Anyhow, you need to see an Ophalmologist for correct diagnosis. Let me know if you have have any clarifications.
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Wish you good health!