Hi, there s a spot on my back in the middle of it, it looks like a nipple. can it be waiting to ripen and stuff comes out of it?

Various: It could be several different growths from a nevus (mole) to other various lesions. I would see a dermatologist for a diagnosis to make sure it is benign.

Cyst: The growth on your back could certainly be a cyst that has a central pore. The opening is the dilated pore and with side-ways pressure may express some material. If the area becomes inflamed , then please seek medical attention.

"lump" on back may B: many things: infected pimple, boil, epidermal inclusion cyst, ingrown hair, et al. Many of those should respond to heat applied to draw them to head so they'll drain. T be certain the lesion isn't something more serious, see PCP for exam of lesion. (S)he can then best advise you how to proceed.