It could be trochleitis/ trochlear tendonitis. Pain is exacerbated by eye movements looking down and inwards, and especially in supraduction (looking up) and looking outwards, which stretches the superior oblique muscle tendon.
Treatment consists of corticosteroid shots to the affected area.

Can you explain why it suddenly happened? and is there any alternative way other than steriod please help

In most cases it is unknown what caused the trochleitis, (meaning it's ideopathic.) Most patients that present with idiopathic trochleitis are in good health and experience relief of their pain after a week's regimen of oral nonsteroidal anti-inflammatory medication. Patients have a 25% chance of relapse within one year of the initial presenting episode.
As for the treatment, the only thing I found was the shots. Of course, the doctor will give you eye drops or something to numb the area before giving you the shot.