Sorry for late reply.
Bro did you adjusted the clutch lever? As per me its problem with your clutch lever, its not adjusted properly thats why gear is so hard.
If gear lever is not adjusted properly following problems may occur
- Hard hear shifting
- Kharak sound on engaging gear while in stationary position
- While holding clutch if you engage gear bike may move forward.
Also check your chain, to tight chain also results in hard gear shift.