Have Plantar Fasciitis. Lower Foot Pain, Painful Injections. What Can I Do?

Hi i have plantars facilitus which ive had since before xmas, i went to physio been doing exercies both in my job as a gymnastic coach ones from hosp and what i researched on internet about the condition, had ultra sound 3 or 4 times a fortnight told see how go now without which helped the dreadful soreness in my heels the pain has now started to change . I have pain in lower foot like i bad sprain and pain going into my calf musles and knees it comes and goes when im walking i have to limp sometimes take stops it throbs . I was offered injections which i was told are painful and i would need time off work 2 weeks poss to rest, Im both self and have employed work in my employed work my major set of income i have a nightmare young boss if i was to have time off she would give my work to another coach and i would loose my job. I cannot afford to loose it and i love my work , i tryed to claim money due to shoulder injury couple of years ago but was told i could not and it was stressful trying without success getting money .Why has my pains changed , whats causing it and what can i do ? is injections my only option?