I have lipoma since 5 years on my arm , now it's a bit bigger 1.5 cm to 2 cm , it's hurt a bit when i pres can this be cancer grow or normal grow?

Unlikely: Cancer tends to be very hard and grow very fast. It would be unlikely that a mass you had for 5 years is cancer. Still, if it growing now you should have it checked. A biopsy will prove that it it benign and It is easier to remove when it is 1.5-2 cm than when it is 10 cm

Both: Most likely this represents a non-malignant growth. However, saying that, since it is getting bigger and is painful with palpation, I would recommend seeing a surgeon and having removed. This will give you the diagnosis and is less involved when it is smaller.