Screeching noise from wheel

So my drivers side wheel has been making a screeching noise while in motion. Sound started while steering left and then, to the right later on. One side or another. Then is slowly started to make the sound no matter which way you steered (over about a month or two) we originally thought it was a rock. We took off the wheel and looked for rocks. We couldn't find any and out the wheel back on. Over the next month is when the noise got louder and louder. No when we took off the wheel, the rotor will wiggle about 1/4 inch forward and back. I don't think it did this before. Anyone have an idea as to whether it is the axle or wheel bearing? We would take it to the mechanic, but we are low on funds and can install the parts ourselves. (Side note: the wheel bearing on the left rear is bad and makes a constant humming sound.) Thanks ~ K