My left arm is having a harder time lifting weights than my right?

okey, so i've been lifting weights recently and i've noticed that my left arm is way more difficult to lift up than my right arm. i am right handed, but i still think something is up cuz it doesnt really feel like its the muscle thats to tired. it feel like the tendon in my arm just doesnt want to curl anymore. and it also gets kinda tight afterwords when im done working out. it feels like im stretching my tendon each time i extend my arm. im pretty sure my technic is good, so i dont think im gettting this feeling cuz im doing something wrong with my workout. is this normal and will it go away?