I have a lump underneath my armpit, its lima hard but moves and its a little painful, should it be any cause for concern?

Sounds like a transient Axillary lymph node inflammation, caused usually in response to infection or inflammation anywhere in the upper limb of same side. This is usually a normal response. But if one nicked their armpit while shaving or so; a warm Epson salt soak for 5 to 10 minutes once or twice a day usually provide relief. For persistent symptoms, see PCP

My suspicion is that it's an ingrown hair that's inflamed or becoming infected. Apply warm compresses. Apply an antibacterial ointment. If it becomes larger,reddened,more tender, have it examined by a physician. Don't use deodorants at this time.