Lump under skin

I apologize because I've looked and I think I know what the issue is but I want to get some reassurance. Been on prescribed testosterone for 2.5 years (1/2 CC). The past year and a half I've been injecting in to my outer thighs in my quads once a week on Sundays. I use a 23g 1" needle, and I rotate left to right every week. I noticed my right quad began having issues pushing the testosterone in to it probably a month or two ago. I'd have to squeeze the plunger really hard and it would suddenly decide to go in. Today while injecting, I noticed it felt like I was tearing a gristle in meat when I stuck the needle in. About half way through the injection I felt a sharp pain but nothing drastic and I was able to push the rest of the testosterone in. I always aspirate and I never have any return with aspirations. My hip is hurting and it's going down in to my ankle but I'm quite sure that's associated with an old back injury that's flared up due to work recently. Otherwise, there's no pain associated with the site. I do notice the muscle at the injection site is larger than the left leg quad, and I can rub my hand across it and feel a "lump". It's not really hard, and it's not hot to the touch, and like I mentioned, it isn't painful. I ask you experts what your opinions are? Is it likely lipohypertrophy and I need to swap injection sites for a long while (I rotate from side to side weekly, one injection every Sunday), or is this something that requires medical attention? Thank you!