Ive been very sick for the past 3-4 days with a bad flu, but the past couple of days ive woken up with a weird soreness in my eyes sometimes it stays the whole day, they arent red or bloodshot or anything, but when i look sharp in any direction, i feel a deep pain coming from behind my eyes, is this part of a bad flu or something more serious? I remember having it once but i cant remember what from