Please don't sit continuosly at computer for long periods at a stretch. Always give rest to your eyes after 30-40 minutes of work and while at work don't stare for long on the computer screen.Always let your eyes blink in between. This will reduce the strain on the eyes.
Contact an Ophthalmologist and get your eyes checked before concluding that it is a migraine
Couging can cause rupture of few small vessels due to the pressure of the process of coughing.This can result in blood during cough. But you should have an X-Ray of Chest PA view done along with complete blood count
to rule out any infection.
Hope this is useful to you.Thanks.