Top of left leg suddenly started aching , no other pains leg is not swollen or hot it's an ache that's hard to ignore?

Can't ignore pain: If it's getting worse, then don't ignore it. It's impossible to guess what it might be without some more information or an exam. Some things that come to mind are: inguinal hernia (often from lifting), strained muscle, deep vein blood clot (can happen after long car/plane ride), infection (should look red or feel hot). Try a heating pad or ibuprofen. If it doesn't improve, go see someone.