Lo Loestrin spotting


I’ve been on the pill for 4 months now and had irregular spotting the first few months but this past month I had no spotting but usual period at the end of the pack... now I’m on the second week of a new pack and am spotting? Is this normal? I’ve been taking the pill regularly haven’t missed it. Is this just a side effect of lo Loestrin that happens randomly? My boobs are also sore which is typical as well.