Almost 2 months after a tooth filling i have sensitivity only when i bite crunchy things no pain at all, is it normal?

Can be normal: Depends on how deep the filling was, the periodontal condition of the bone around the tooth, and if the tooth had root canal therapy. Have your dentist take a quick look at it.. It is probably fine, but you really want to make sure.

sensitivity: You need to see the dentist that placed the filling it may be in high occlusion and need a simple adjustment 2 months for this is too long.

No: It happens but not normal. The tooth may be weakened and flexing with the increased force needed to break the crunchy things. A crown may be needed to protect this from breakage. Also, there may be a crack in the tooth at or below the edges of the filling. See your Dentist to evaluate this before you break something and possibly lose the tooth. Good Luck.