More specifically to weight lifting, compound lifts: squats, deadlifts, bench press, and overhead press. (also rows)
As far as exercise related pain goes, the general rule is that sharp pains are bad (e.g. go see a doctor and get an xray/mri/scan) and dull throbbing pains are okay. Weight lifting can bring out dormant injuries as inactive muscles become activated and the body recomposes itself. These usually are treated with stretching, trigger point therapy, cupping and with time diminish significantly.
The Wendler 5/3/1 Program is very time efficient. There's an explanation of the program here in an interview with body builder by the name of Matt Ogus. http://www.simplyshredded.com/rising-star-natural-bodybuilde...
There's thousands of variations of exercise "programs" out there but the fundamentals are the same.
1. show up consistently
2. move weight at high intensities (>60%) to induce muscle hypertrophy
3. eat a lot (to gain muscle) || eat a little less (to lose fat) || eat adequately to maintain. (caloric surplus/deficit/maintenance)
Intensity refers to a percentage of your maximal weight that can be moved once. There are some calculators that can also calculate your 1-repetition-max based on the maximum.
One other piece of advice for myself is that I have very dry skin and using any type of soap on a daily basis dries out my skin pretty badly. As an Asian that lacks the specific type of sweat glands with BO, I've made showers that are time efficient by merely washing with water only. Soap is used sporadically, but 98% of daily showers are with water only. Anecdotally, other nationalities on reddit have reported success with water-only showering.
I can drive to the gym in 5 minutes, do several sets in 20-45 minutes depending on which compounds I am targeting, then be back home and spend another 5-10 minutes on a shower. Time is further made efficient by standardizing my tops with black t-shirts, so very little time is spent on choosing clothing.
Home versions of this is possible has well with a set of dumbbells, but if you have any strength, it is quite possible to outgrow the dumbbells in relatively short amount of time.
Glasses also don't get in the way of weights, other than wiping sweat underneath them between sets, but there aren't swift fast movements that jerk the face such that glasses are flying off of the face or a ball will knock one's glasses off.
For chronic conditions that inhibit intense activity, it may be worth looking at the concepts introduced by Terry Wahls in her Ted talk: http://terrywahls.com/minding-your-mitochondria-dr-terry-wah...
I got her book and it is repetitive, but the basic premise from this MD is that the body is a chemical environment and chemical deficiencies lead to malfunctions. As it is obvious that plants won't thrive without fertilizer and water, the same goes for human nutrition. Her solution is consuming food sources with 2-3 cups each of greens, 2-3 cups of sulfur (broccoli, cabbage, etc), 2-3 cups of color (blueberries, tomatoes, blackberries) & 4-6 oz of nutrient dense meat on a daily basis.
I found a tremendous amount of quality of life improvement by adding the greens/sulfur/color just several times a week as well.